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Sundstrand Model 90

1. 33 Charge Pump Assembly 33 Bearings 33 DISASSEMBLY AND ASSEMBLY OF HYDROSTATIC PUMP 34 PUMP HOUSING DISASSEMBLY AND ASSEMBLY 37 DSC 37 Assembly of Pump Housing 38 Assembly of Pump Section 38 REMOVAL AND REPLACEMENT OF ACCELERATION VALVES 40 Disassembly 41 Assembly an a 4 DISASSEMBLY AND ASSEMBLY OF HYDROSTATIC MOTOR 41 Disassembly of Motor 41 Assembly of Motor 45 DISASSEMBLY AND ASSEMBLY OF CYLINDER BLOCKS AND PISTON ASSEMBLIES 46 HYDROGEAR SECTION 47 Hydrogear Trouble Shooting Chart 48 Trouble Shooting Guide 49 Preliminary Checks as snn sss AE NY 49 Hydrogear Tune up 49 Hydrogear Service Note 50 Check Valves mm 51 Charge Relief Valve 52 Towing Valve 52 Implement Relief Valve 52 Hydrogear Removal and Replacement 52 HYDROGEAR TRANSMISSION PARTS DRAWING 54 HYDROGEAR PARTS LIST
2. 55 HYDROGEAR PUMP SHAFT SEAL REPLACEMENT 56 THE TRANSAXLE 57 Removal of Transaxle Complete with Hydrostatic Unit 57 Removal of Hydrostatic Unit from the Transaxle 57 Transaxle Disassembly 57 Parking Brake and Oil Filter 58 Transaxle Gasket Installation 59 PISTON PISTON HYDROSTATIC PARTS DRAWING 60 PISTON PISTON HYDROSTATIC PARTS LIST 61 PRINCIPLES OF OPERATION Refer to the Neutral Forward amp Reverse Schematic Diagrams Figs 1 Pg 6 2 Pg 7 3 Pg 8 Power is transmitted from the engine through a flexible coupling or belt and pulley arrangement to the pump shaft shown at left of diagrams Rotation of the input shaft causes the main pump cylinder block and the charge pump to turn initiating the power transmitting function Oil from the reservoir is drawn by the charge pump through the inlet strainer and forced by way of the check valves into the low pres sure lines Oil introduced by the charge pump fills the area in back of the cylinder block pistons holding them against their swash plates in both the pump and the motor When the pump swash plate is in neutral the pump cylinder block pistons do not move in and out Thus in neutral no oil is being pumped from the variable displacement pump Low pressure oil from the ch
3. DISASSEMBLY AND ASSEMBLY OF CYLINDER BLOCKS AND PISTON ASSEMBLIES NOTE Although the pump cylinder block and the motor cylinder block assemblies are similar they are not alike NEW UNIVERSAL CYLINDER BLOCK PREVIOUSLY USED IN MOTOR ONLY SPLINE MAS RELIEF AND COUNTERBORE TO BE USED IN BOTH PUMP AND MOTOR OUD PUME TYPE CYLINDER BLOCK FULL SPLINE BE USED IM PUMP ONLY FIG 86 Cylinder blocks and pistons are serviced as a kit However they may be taken apart for cleaning and inspection Note the position of each piston so that it may be returned to its original cylinder bore FIG 87 Cylinder Block Washers Springs and Spring Seats Disassembly 1 Remove the pistons slippers and slipper re tainer assembly from the cylinder block See Fig 88 2 Make up a special spring compressor made from 3 x 3 long hex head bolt nut 3 SAE washer and 3 x X washer 3 Center the X washer on the cylinder block spring retainer Insert the 3 x 3 bolt through the washer and on through the cylinder block Place the SAE washer and nut on the end of the bolt and tighten the nut until the spring is compressed 4 With the spring compressed remove the spi roloc retaining ring 5 Loosen and remove the compressor and remove the outside retaining washer spring and inside spring seat NOTE The pump cylinder block incorporates a flat washer for the inside
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5. WNOd33d NOILIQNOO YO dN 4901 TVOINVHOAW AINO NO112331da JNO NI 3MOd YOLOW dWAd JVIDOJAAH JOVWVd YO UVIM TVNSJINI qassvdAd ONI38 SI 38 NYD L di 5 4 AJI JAIVA ONIMOL 35012 SX2V1 YO JON YOLIVIL NOHL23S 831N3O2 NI JATVA ONINOILONNITYW JOVANIT NI vagas 13A31 YadOUd OL TU 13411 110 MOI YO 1531 ien VO 318ISSOd NOILLIONOD LAVH ONILOOHS 318n081 4YI1904GAH JOVANI 1ONWINOO ALINVA 4 081 TWWYON SIVIHAJAO IVIOOYCAH AB TROUBLE SHOOTING GUIDE This trouble shooting guide is designed to help determine if a Hydrogear can be repaired within the limits of authorized service procedures or if the assembly must be replaced First listen carefully to the operator s description of the problem Then operate the tractor to confirm ihe condition Hydrogear transmission malfunctions usually show up in one of the following ways 1 Tractor will not operate in either direction includes conditions ranging from completely inoperative to lack or loss of power in both directions 2 Tractor operates in one direction only much the same os item 1 except that it applies to one direction only J Erratic engagement sharp jerky or abrupt acceleration and braking in one or both direc tions 4 Transmission overheats likely to accompan
6. u SA RES IN SNES ERE RD LY 3H3HdSOWLV E UOAYISIU 3UNSSIYd ISVI E lt 3UNSSIUd H NA N 56 EZ Z nouons 7 2 CS b NEN 31114 uanivaus NE p KAZ g N x e 2 fe ad EN PAZ Z YOLOW 1N3W32V1dSIqQ 7 d n r gt em Ge 2 ZEEE RE Z 1N3W32v14S a IIAVIYVA ki HAT 9 2 60 4 n A 14vHS 14VHS r4 4 A oe n MAS EE 7 ILVIdHSYMS INdINO EN 4 Z 318VINMVA dWNd MOLOW FA ML Z RSR An F1V1d ONIAIVA CSS ras Dose Lec po y NITTI LO on M ee Tr ICE Lt ANITA ZA Y I wi dai SEO EA ASTRI OT is EST 5 W NI rss ASA A fat ANN FA ANT AA a KU 7 7 PASAY AR N 3ATVA ONI133HM 3331 a 25 A18W3SSY S3A1VA 23H2 4 13018 at E EAA WIGNITAD 3 JLVIGHSYMS A ESTIS van ists EEE RES 4 x LA 1 7 NO PI 3 JZA 3SM3A3M Hf A Y v n sas 7 AMS KON n 1VULn3N 3A1VA TOULNOJ 1N3W31dWI OL JATVA 1OHLNOD WOUJ P
7. E NM i tuus 48 vi MSS o TE aes A SUPPLEMENT SUPPLEMENT SUPPLEMENT Valve Plates Note the difference between the pump and motor valve plates Fig 44 Ensure the correct valve plate is ordered when replacing as the motor plate will fit in place of the pump plate but will not function properly Scratches in the brass surface of the plate that can be felt with a fingernail indicate an unserviceable valve plate The cylinder block may also be unserviceable in this case Charge and Implement Valves Note the location of these valves depending on whether the tractor has manual or hydraulic lift Fig 61 Using the appropriate valve parts in the correct hole permits setting up any piston piston unit for either type of lift system Charge Pump Refer to the installation of the charge pump Fig 49 With the pump end cap positioned as shown note that the dowel pin is down nearest the sealing surface of the pump end cap The charge pump can be put on upside down and will fail to function Also note that the charge pump needle bearing Fig 54 must protrude above the housing surface to hold the valve plate in place Use care to prevent accidentally pressing the dowel pin into the housing Be sure the valve plate noich is over the dowel pin on assembly or the valve plate will be ruined Control Shaft Stub Shaft On 1978 and later transmissions the longer control shaf
8. N G e mak ank mak VIN NBA NO SB 4 ABN BA j gt HYDROGEAR PARTS LIST Parts available only through Authorized Dealers When ordering parts always list Part No and Description Specifications subject to change without notice PART nr Hn DESCRIPTION Ba 58 5998 Plate Tension 2 59 909000 Screw Round Head 8 32 x 2 60 5996 Cam 1 61 920229 Washer 2 62 920078 Lockwasher 8 2 63 933196 Roll Pin X x 2 64 7266 Valve 65 7268 Ring Back Up 66 971113 O Ring 2 67 7267 Plug 1 68 6444 Assembly Dampening Valve with O Rings 2 69 970118 O Ring 2 70 971015 O Ring 2 71 7054 Assembly Piston amp Sleeve Matched Assembly 2 72 971018 O Ring 2 73 7264 Spring Relief Valve 2 74 7052 Spring Relief Valve 2 75 7051 Seat Spring 2 76 7050 Cone Relief Valve 2 77 7049 Sleeve 2 78 971017 O Ring 2 79 7752 Plug 7 80 7753 Spring Check Valve 2 81 7754 Valve Check Valve 2 82 7755 Spring Charge Pump Relief Valve 1 83 7756 Cone Relief Valve 1 84 943462 Plug Pipe Hex Socket 4 14 1 85 973310 O Ring 7 86 7877 Seal PUMP SHAFT SEAL REPLACEMENT Replacement of the pump shaft seal Fig 91 is accomplished without removing the Hydrogear as sembly from the tractor Raise the seat Rem
9. 10W 30 or SAE 10W 40 engine oil IMPORTANT 1972 and prior and some 1973 models use automatic transmission fluid Dexron Il Determine type of oil in these units Do Not Mix engine oil and automatic transmission fluid Units may have been changed to engine oil during prior overhauis To convert to engine oil the entire system transmission transaxle hoses hydraulic lift valve must be totally cleaned of transmission fluid e Pressure Checks Keep in mind an unsealed condition anywhere in the transmission will cause a low or no charge pressure condition Troubleshooting charts and the lack of charge pressure seem to point to the pump section as the source of the problem Experience shows most loss of pressure conditions to be due to sticking acceleration or forward reverse check valves charge pressure relief valves or a problem in the motor section Motor section problems are most commonly snap ring special retaining ring or spiraloc retaining ring failure causing the motor cylinder block to lose its spring preload against the valve plate Contamination Where dirt or failed parts have circulated through the system it is essential the entire system be disassembled and flushed clean both transmission sections the transaxle hydraulic valve and hoses or hydraulic manifold Residual contamination will quickly destroy the repaired unit Supplement 2 XO I m 44 toua 4m iN3W31ddhSs
10. 5966 5999 908143 908038 908043 915113 908034 5969 933152 5990 5991 5992 6155 943346 943004 5955 943460 7880 5993 911037 6826 972116 5994 933215 970026 5995 909849 DESCRIPTION Case R H Bearing Needle 1 I D Bearing Ball 1 2 D Bearing Needle 1 D Seal 1 D Seal Brake Shaft 2 D Pin Dowel Case L H Bearing Needle 1 D End Cap R H End Cap L H Axle Rear R H Axle Rear L H Snap Ring Washer Thrust Gear Axle Gear Differential Ring Body Roll Pin x 2 Gear Differential Pinion Spring Cylindrical Bolt 2 16 x 374 Nut Elastic Stop s 16 Washer Flat a SAE Gear 44 Teeth 11 Teeth Gear 22 Teeth Gear 33 Teeth Shaft 1 Dia Snap Ring 1 Shaft Key 9 Woodruff Assembly Park Brake Gasket Case Bolt Hex e 16 x 5 Bolt Hex a 16 x 2 Bolt Hex 28 16 X 3 2 Nut Nylok 3 s 16 Bolt Hex Nylok s 16 x 1 Assembly Lever Brake Roll Pin x 3 4 Assembly Filter Fitting Strainer Assembly Dipstick amp Filter Nipple Pipe x 3 2 Coupling Pipe Gasket Pump Plug 4 Pipe Assembly Hydrogear Unit Complete Support Cam Block Screw Socket Head 4 20 x Shim O Ring Arm Cam Follower Roll Pin x 17 4 O Ring Eccentric Cam Follower Set Screw Nylok 4 20 x 16 55 NO REQ D N
11. CYLINDER BLOCK ASSEMBLY REPLACE REPAIR OR REPLACE REPLACE SERVICE AREA Pump cooling fins Push valve Acceleration valves Charge pressure test Entire hydrostatic unit standard system Entire hydrostatic unit separated system Charge relief valve Implement relief valve Motor thrust plate Hydrostatic motor Slipper retainers Piston slippers Cylinder block assembly Parking pawl Transaxle gears GENERAL INFORMATION Page 34 Page 5 Page 5 Page 24 9 a e a 6 4 Page 33 Page 32 Page 32 6 17 Page Page Page Page Page Page Page Page Page Page Page REMOVAL REPLACEMENT 26 27 35 35 42 Al 46 46 46 58 57 SPEED CONTROL LINKAGE AND ADJUSTMENTS Standard System NEUTRAL ADJUSTMENT Place the tractor on a level surface with the engine running Depress the brake pedal The tractor should not creep and the rear wheels should be effectively locked Some creeping on slopes is normal and cannot be completely prevented If the tractor creeps on a level surface while in neutral adjust as follows 1 Block the rear wheels off the ground 2 Remove the access plate located in front of the seat 3 With an allen wrench loosen the set screws in the arm see Fig 4 4 Depress the brake pedal and keep it depressed Start the engine and disengage the parking brake Insert
12. Ring Metering Plug O Ring Ball Spring Acceleration Valve Assembly O Ring Back Up Ring O Ring Motor Gasket Formerly 200191 Motor End Cap Valve Plate Cylinder Block Kit Consists of nine pistons and a cylinder block not available separately plus the correct number of items 70 71 72 73 amp 86 Retaining Ring Washer Spring Retainer Retaining Clip Acceleration Valve Spring Pipe Plug Formerly 200199 Motor Cover Plate Cap Screw Motor Shaft Formerly 200197 CapScrew Formerly 200195 Centering Pilot Formerly 200194 O Ring Seal Retainer With O Ring Formerly 200196 Needle Bearing Formerly 200192 Slipper Retainer Thrust Plate Formerly 200188 Motor Housing Ball Bearing Retaining Ring O Ring Copper Washer Socket Head Cap Screw Formerly 200186 Hex Head Cap Screw Tractors not equipped with a hydraulic lift use spring No 103455 here and only the plug item 51 and o ring 50 on the opposite side 62 D m Oz DO AY G ND ND NI PP St n A N mak AA A ABN _ Bulletin No Date Issued SERVICE BULLETIN RECORD Topic or Part Involved Hydrogear Bulletins 62 3 65 Hydrogear Transaxle Gasket Replacement 64 4 65 Hydrogear Kit 6059 for use with Sickle Bar mower 67 7 65 Hydrogear Oil leak due to loose slide casting 68 9 65 Hydrogear Kit 6066 for correcti
13. clear the motor pad 2 Jack the tractor up under the frame and remove the left rear wheel for working space Place an oil drain pan under the motor and transaxle to catch oil as the motor is removed To remove the motor remove the top corner motor to case bolt nuts and the two lower motor to case cap screws which thread into the case PUMP REMOVAL l To remove the hydrostatic pump disconnect the head lamp wires and remove the hood grille and shroud assemblies Disconnect and remove the battery and disconnect the PTO rod trunnion from the clutch bar 2 Disconnect the fuel and suction lines from the engine and the coil wire from the coil Next disconnect the throttle arm ball joint and the choke wire assembly from ihe carburetor and engine 3 Disconnect the cable from the starter and re move the four 4 bolts holding the engine to the frame 4 Pull the engine straight forward until the coupling slides from the pump shaft spline 5 It is not necessary to lift the engine from the frame If however you would like to get it completely out of the way disconnect the DC wire from the voltage regulator connector and the engine will be freed to move as desired 6 Remove the right console panel together with the battery supports 7 Disconnect all three control rods The upper forward rod is connected to the speed control lever linkage The long rod coming up from the bottom is connected to the brake pedal shaft ar
14. oil shown in black closes the high pressure check valve and travels through internal passages to the inlet side of the piston motor In the motor high pressure oil acting on the back of the piston forces the piston down the incline causing the block to rotate and turn the output shaft REVERSE TRAVEL When the control handle is moved to the reverse position the pump variable swashplate is tilted in the opposite position which changes the direction of oil flow The high and low pressure circuits interchange causing the motor to rotate in the opposite direction ACCELERATION VALVES The acceleration valves are placed in the circuit to limit vehicle acceleration to a safe rate With the con trol lever in neutral oil is under low pressure through out the circuit When the control lever is advanced the circuit pressure increases causing the oil on the high pressure side to bleed by the flats on the valve lands and into the low pressure side This high pres sure oil continues to bleed to the low pressure side by passing the piston motor and holding the accelera tion rate to a safe level during the time it takes for the acceleration valve to close against its seat The delay in closing the valve is due to the time it takes the high pressure oil to bleed through the small orifice in the acceleration valve metering plug and into the area behind the valve PUSH VALVE When open the push or free wheeling valve ollows the oil to by
15. spring seat The motor cylinder block incorporates a special spring seat retainer which also serves as the stop for the motor shaft spring clip FIG 88 Before removing Piston Mark both Piston and Cylinder Bore with Tape FIG 89 Remove Retaining Ring using special Compressor Tool Assembly 1 Install the inside spring retainer in the cylinder block washer if a pump cylinder block special retainer if a motor cylinder block When installing the special retainer in the motor cylinder block make sure that the large end is placed toward the spring 2 Install the spring in the bore of the cylinder block 3 Place the outside retainer washer on the coil spring 4 Using the special spring compressor tool com press the spring and install the spiroloc retaining ring E HYDROGEAR SECTION 47 IVISOYTAH TIVISNI SIYOd FAOWIY x YO ANYIC 0399015 SNIJ IV IN3WIOVONI 211V133 SNIJ ONITOOD NY312 NOll1VdddO INIONI 1531 NO 039901 1139 323H2 4 SI HOIHA 33S OL JIXVSNVYL WOUJ x 31vauvd3s HSNd LON THM LI dl SNOI123MIQ JOJIVAL HSNd OL AJI JATYA ONIMOL N3dO HiOd NI YIMOd SAIVT JON TIM 8OLVal DLLYVW W 193HM JOVd dA JNAL
16. strainer for metal particles If metal particles are found carefully inspect the internal parts of the hydrostatic unit for damage TRANSAXLE DISASSEMBLY The transmission case is held together with six bolts Disassembly may be made from either side leaving the gears intact in the opposite side NOTE It is not necessary to remove the hydrostatic unit if only the transaxle is being serviced 1 Remove both wheel hubs by loosening the lock nuts and set screws Slide the hubs from the axle A special wheel puller may be required 2 Remove the woodruff keys and file any rough edges from the key slots and the ends of the axle 3 Remove the six bolts holding the transmission case halves together 4 Lightly tap the half to be removed with a plastic or rawhide mallet to break the seal Slide the case half off the axle carefully to avoid damaging the oil seals 5 Remove the old gasket and carefully clean the sealing surfaces l Matta GAS Ghar T FIG 100 Disassembled Transaxle 24 Pm DIFFERENTIAL CASE HALF BULL GEAR PINION GEARS PINION GEARS DIFFERENTIAL CASE HALF SNAP RING NUTS AXLE GEAR FIG 101 Disassembled Differential 6 Carefully slide the differential assembly out of the case 7 Remove gear assembly consisting of Nos 103395 101887 and 102781 Also remove large gear No 101885 intact 8 Slide gears off of the No 5965 shaft 9 Remove the fo
17. the belt guard or fan guard de pending on model Test operation and check for leaks END OF HYDROGEAR SECTION THE TRANSAXLE This section is written in general terms to cover all automatic transmissions currently being used by Wheel Horse REMOVAL OF TRANSAXLE COMPLETE WITH HYDROSTATIC UNIT Jack the tractor up and place jack stands under the frame Remove both rear wheel and tire assemblies Remove the tractor seat and fender assembly by re moving the hardware holding it to the transaxle Re move the drive belt from the transmission Remove any access plates Drain the transmission oil through the transaxle drain plug if desired Place a jack under the transaxle and remove the cap screws holding it to the frame Lower the jack and remove the entire transaxle assembly REMOVAL OF HYDROSTATIC UNIT FROM THE TRANSAXLE If the transmission oil has not been drained place the entire assembly in an oil drain pan Remove the two 3 top corner motor to case bolts and nuts and the two lower cap screws that thread into the case Carefully remove the hydrostatic unit from the transaxle allowing the oil to drain as it is removed Make certain that the control cam comes free from the cam pin ball stud Now the magnetic strainer is accessible FIG 98 Hydrostatic Unit Gasket Strainer and Transaxle Remove the strainer and wash with solvent when ever servicing the transaxle Check the magnet at the end of the
18. the front bracket from the top under the fuel and hydraulic hose and in front of the parking brake lever Turn the assembly as needed a 4 4 gt gt P i a FIG 34 Seat Pivot Installation Line up the adjustment handle at the rear of the spring block Hold the front of the pivot assembly to line it up with the holes in the frame and install the seat pivot rod Retain with e rings at each end Install the seat stop bar with its rubber cushions and bolt it to the seat pivot bar Using the nylon bushings and hairpin cotters reinstall the seat assembly Reinstall the access plate and the parking brake lever knob MOTOR INSTALLATION The following photograph of the transaxle shows the motor mounting area with the intake screen pulled out The two cap screw holes on each side of the screen and the two top corner holes are for the four bolts which retain the motor to the case FIG 35 Motor Mounting Area a BO a The following photograph shows the acceleration valves and related parts removed from the motor The valve at the right is complete The valve shown at the left has had the metering plug and ball and spring removed NOTE Two valves with the spring between them and the two plugs with o ring seals make up the complete acceleration valve assemblies To install place the spring in the end of one of the valves and install the valve and spring assembly in o
19. the speed control lever into forward or reverse CHARGE PRESSURE TEST Charge pressure is an indication of transmission condition Connect the pressure gauge as shown in Fig 13 to the 4 pipe plug located between the imple ment hose ports The alternate port straight thread just above this port may be used if it is more con venient With the engine running at throttle the charge pressure should be 70 to 150 PSI The pressure must never drop below 50 PSI under any condition Always take pressure tests when the transmission oil is cold TRANSMISSION CONTROL LINKAGE FORWARD Qu 12 FORWARD REVERSE LEVER TENSION ADJUSTMENT SHIFT ROD ARM ES BRAKE NEUTRAL DS PEDAL A ki Dd BRAKE LEVER S n ASSEMBLY NA FIG 13 Charge Pressure Test Separated System and again after the transmission has reached operat be 550 to 700 PSI when the piston has reached the ing temperature An appreciable drop in charge pres end of its stroke sure as the temperature rises indicates internal leak age caused by worn parts resulting in loss of power REPAIR PROCEDURES On B and C Series tractors and other standard system tractors the hydrostatic pump and motor are bolted together as one unit Fig 15 On the 1973 18 HP Automatic and all D Series tractors the pump and motor are separated to accommodate the design incorporating a manifold between the pump and moto
20. using a small magnet to withdraw them from the bore The acceleration valve sleeve 3 Fig 91 and relief valve seat 8 Fig 91 may now be removed This is best accomplished by inserting a stiff wire hook into the drain port in the side of the seat and pulling See Figs 91 Fig II The force necessary will de pend on the radial press of the sealing O rings on the sleeve and seat SEAT PULLER HYDROGEAR SERVICE NOTE PROBLEM Tractor will not operate in either direction Problem usually occurs suddenly with little or no warning CAUSE Internal plug b is either loose has fallen completely out of position FIGURE SOLUTION 1 2 50 Remove the side socket head plug c using a X Allen wrench Insert the long arm of a 32 Allen wrench into the horizontal passage exposed in Step 1 across the large vertical passage and deter mine if the internal plug is in place If the internal plug is in place but is loose tighten it securely and replace the side plug If the internal plug is not in place use a 7 Allen wrench to remove the top plug a The internal plug is usually found at the bottom of the large vertical passage Retrieve it with a magnet Insert the internal plug through the horizontal passage across the large vertical passage and tighten it securely in place Then reinstall both the side and top plugs FIG 92 NOTE A large amount of iron or bra
21. 35 200238 Pump End Cap 1 36 200241 Socket Head Plug 1 37 200226 Socket Head Plug 1 38 200227 Pipe Plug 1 39 83 3830 Pipe Plug 4 Formerly 200199 2 40 83 3730 Cap Screw Short Formerly 200184 2 41 103216 Ball 2 42 103457 Check Valve Spring 2 43 973310 O Ring 2 44 103458 Check Valve Plug 2 45 971012 O Ring 1 46 103459 Back Up Ring 1 47 103460 Push Valve 1 Refer to specific tractor parts manual to determine replacement parts information for 1978 1980 tractors Specifications subject to change without notice a6 PARTS LIST 1973 1977 PISTON PISTON HYDROSTATIC TRANSMISSION Parts available only through Authorized Dealers When ordering parts always list Part No and Description Specifications subject to change without notice ITEM PART NO NO 48 103216 49 103455 50 9 3310 51 7752 52 103465 53 103588 54 103574 55 103464 56 6632 57 103593 58 973500 59 103591 60 973190 61 103590 62 103589 63 103588 64 971015 65 103184 66 971018 67 83 3760 68 200193 69 200203 200190 70 200208 71 200209 72 200210 73 200211 74 200204 75 103592 76 83 3830 77 103840 78 200200 79 105124 80 83 3790 81 83 3780 82 200205 83 83 3800 84 83 3770 86 200212 88 83 3750 89 200189 90 200187 91 200206 92 970132 93 200185 94 83 3740 95 200202 DESCRIPTION Ball Charge Relief Valve Spring O Ring Plug Plug Acceleration Valve Body Shim Set Implement Relief Valve Spring Relief Valve Cone Hex Plug O
22. AR FIG 83 3 Install the valve plate with the steel side toward the motor end cap making sure it is centered over the needle bearing and over the end cap dowel pin FIG 85 Install Piston Cylinder Block Assembly 7 Slide the cylinder block pistons slippers and 4 Apply 10W30 oil to the bearing surfaces of the slipper retainer assembly on the motor shaft Push it shaft and install the motor shaft with the gear at the in place until the spring retaining clip seats output end of the motor end cap P P 8 Install the ball bearing in the end of the alumi num housing with lettered end out 9 Install the four 16 cap screws through the aluminum housing and install a new gasket over the bolts 10 Install the thrust plate on the swash plate surface of the housing 11 With the webbed side of the housing to the top using the screws as a pilot install the housing over the shaft and push it in enough to start the screws Snug up the screws evenly until the housing is approximately 36 away from the end cap Do not tighten at this time 12 Install the bearing retaining ring on the end of the pump shaft 13 Install the large O ring seal in the housing recess around the outside of the bearing 14 Install the end cover and secure with the four Allen head screws and tighten evenly 15 Push the housing up flush to seat against the FIG 84 Spring Retaining Clip end cap and tighten all four screws evenly
23. ATICALLY INSPECT ACCELERATION INSPECT OK VALVES HYDROSTATIC SEALS DEFECTIVE DEFECTIVE AIR LEAKAGE REPLACE REPLACE REPLACE INSPECT SWASH INSPECT MOTOR PLATE ROLL PINS CYLINDER BLOCK a A INSPECT CHARGE OK CHECK VALVES DEFECTIVE DEFECTIVE SERVICE AREA GENERAL INFORMATION REMOVAL REPLACEMENT Acceleration valves Page 5 Page 40 Charge check valves Page 36 Seal rings standard system Page 26 Seal rings separated system Page 29 Shaft seals Page 32 Page 37 44 Motor cylinder block Page 32 Page 43 Swash plate roll pins Page 37 TRACTOR OPERATES IN BOTH DIRECTIONS BUT WITH LOSS OF POWER CONDITION BECOMES WORSE AS TRANSMISSION BECOMES HOT INSPECT PUMP AND MOTOR VALVE PLATES INSPECT OIL SUPPLY TEST CHARGE PRESSURE CONTAMINATED DEFECTIVE CLEAN SYSTEM AND REPLACE OIL LOW REPLACE INSPECT CHARGE RELIEF VALVE DEFECTIVE REPLACE OK INSPECT IMPLEMENT RELIEF VALVE DEFECTIVE REPLACE OK INSTALL THRUST PLATE AND REPLACE CYLINDER BLOCK ASSEMBLY INSPECT MOTOR COVER MISSING THRUST PLATE i OK INSPECT HYDROSTATIC MOTOR REPAIR OR LOCKED UP REPLACE OK INSPECT SLIPPER RETAINERS REPLACE DEFECTIVE OK REPLACE CYLINDER BLOCK ASSEMBLY INSPECT PISTON SLIPPERS OK INSPECT CYLINDER BLOCK ASSEMBLY REPLACE DEFECTIVE 3 OK REPAIR OR REP
24. Adjustment Parking Brake Adjustment PRESSURE TESTING Charge Pressure Test Implement Pressure Test REPAIR PROCEDURES TIT 25 Separation of Pump and Motor 25 Seal Ring Installation 26 Assembly of Pump to Motor 26 REMOVAL OF HYDROSTATIC UNIT FROM A STANDARD SYSTEM 26 INSTALLATION OF HYDROSTATIC UNIT IN A STANDARD SYSTEM 26 REMOVAL OF HYDROSTATIC UNIT FROM A SEPARATED SYSTEM 27 Removal 27 7 e e t IQ E ces 27 INSTALLATION OF HYDROSTATIC UNIT IN A SEPARATED SYSTEM 27 Pump Installation lt a 27 Manifold Installation 28 Motor Installation 30 INSPECTION OF PARTS AN 6 32 Pump and Motor Shafts 32 Cylinder Block Assemblies 32 Cylinder Block Face 32 Pistons and Slippers 32 Slipper Retainers 33 Valve Plates 4 33 Thrust Plates
25. D Series Adjustments Transmission control linkage adjustments described in this manual for 1975 models are appropriate for 1976 77 models 1978 82 linkage adjustments are covered in the 1978 79 B C D Series Service Manual P N 810063R1 D Series Driven Coupling Preload and Pump Alignment Refer to Service Bulletins 217 and 305 for special service information CONSTRUCTION CHANGES 1978 AND LATER Sundstrand units on 1978 and later tractors differ from earlier units in that the motor shaft extends through the cover plate for the mounting of a parking brake drum Motor repair operations described in this manual still apply except that the motor cover plate oil seal should be replaced during the repair process Supplement 1 Part way through the 1979 model year the charge pressure relief valve on hydraulic lift models was changed from ball type to cone type Both constructions are illustrated below with part numbers given for the cone type valve system SERVICE NOTES O eo la e 8 REV CHECK VALVE ALTERNATE CONSTRUCTION CHARGE VALVE HYDRAULIC LIFT MID 1979 amp LATER MODELS CHARGE VALVE 6632 SEE 103455 103574 Q 973310 a J 103465 No 2 inet eet yee gina QUE MUCH EMO tni Pert i m rmn mai 5 i n 1 dms 5 gt p e Oil The recommended transmission oil is SAE
26. FIG 7 through the hole in the side panel and rotate the eccentric cam pin until the rear wheels stop This usually occurs at a point midway between forward and backward wheel rotation Re tighten the lock screw holding the eccentric assembly To position the speed control lever at the neutral position of the console slot depress the brake pedal and adjust the length of the shift rod arm by rotating it in its trunnion FRICTION ADJUSTMENT The speed control lever is friction loaded to hold selected speed in either direction If the lever does not remain where it is set during operation the friction may be increased by tightening the adjusting nut through the access hole located in the right panel see Fig 6 The proper amount of friction is obtained when approximately 18 pounds of force at the handle moves the control lever PARKING BRAKE ADJUSTMENT 1 With the engine shut off press and release the brake pedal 2 Engage the parking brake by placing the lever in the rear notch of the access plate 3 Check the need for adjustment by moving the speed control lever back and forth to determine if the linkage can be moved from neutral toward either the forward or reverse positions 4 f the speed control lever can be moved with little effort toward either position as described in step 3 shorten the length of the parking brake lever rod This adjustment is made by turning the nut on the rear of the rod against the trunni
27. JUSTMENT 1 Engage the parking brake 2 Adjust the trunnion 6 29 on the brake rod 6 25 until there is 4 clearance between the washer and trunnion 6 26 at the other front end of the rod 3 Tighten the lock nut at the adjusting trunnion 6 25 1975 D SERIES TRACTORS NEUTRAL ADJUSTMENT An access hole is provided in the right console panel for the neutral adjustment If the tractor creeps when in neutral adjust as follows 1 Block the rear wheels off the ground 2 Loosen the lock screw holding the eccentric assembly Fig 10 3 Depress the brake pedal and keep it depressed during adjustment NEUTRAL ADJUSTMENT 1 B 4 m Fi M ADJUSTMENT SCREW a E Q FRICTION ADJUSTMENT N 4 gt Transmission Neutral amp Speed Control Lever Tension Adjustment FIG 10 4 Start the engine and run it at half throttle Disengage the parking brake Insert a screw driver through the hole in the side panel and rotate the eccentric cam pin to a point midway between forward wheel rotation and backward wheel rotation Retighten the lock screw hold ing the eccentric assembly 5 Increase engine speed to full throttle Move the speed control lever in both directions and re turn it to neutral with the pedal Repeat several times Recheck adjustment and readjust if required To position the speed control lever at the neu
28. LACE INSPECT PARKING PAWL JAMMED OK INSPECT TRANSAXLE GEARS BROKEN REPLACE 14 SERVICE AREA Charge pressure test Valve plates Charge relief valve Implement relief valve Motor thrust plate Hydrostatic motor Slipper retainers Piston slippers Cylinder block assembly Parking Transaxle gears GENERAL INFORMATION Page 24 Page 33 Page 5 Page 5 8 Page 33 Page 32 Page 32 w 9 a REMOVAL REPLACEMENT Page 35 43 Page 35 Page 35 Page 42 Page 41 Page 46 Page 46 Page 46 Page 58 Page 57 TRANSMISSION OVERHEATING INSPECT PUMP COOLING FINS INSPECT PUSH VALVE DEFECTIVE CLEAN FINS REPLACE CHECK CHARGE PRESSURE REPLACE ENTIRE HYDROSTATIC UNIT LOW INSPECT CHARGE RELIEF VALVE DEFECTIVE OK INSPECT IMPLEMENT RELIEF VALVE DEFECTIVE OK INSPECT MOTOR COVER THRUST PLATE MISSING OK INSPECT HYDROSTATIC MOTOR LOCKED UP OK INSPECT SLIPPER DEFECTIVE RETAINERS OK INSPECT PISTON RN SLIPPERS Tw OK INSPECT CYLINDER BLOCK ASSEMBLY DEFECTIVE OK INSPECT PARKING PAWL JAMMED OK INSPECT TRANSAXLE GEARS BROKEN INSTALL THRUST PLATE AND REPLACE CYLINDER BLOCK ASSEMBLY INSPECT ACCELERATION VALVES DEFECTIVE REPLACE REPLACE REPLACE REPAIR OR REPLACE REPLACE REPLACE
29. LI AUTOMATIC TRANSMISSION REPAIR MANUAL SUNDSTRAND HYDROSTATIC SYSTEMS Hydrogear amp Piston Piston 1965 1982 WHEEL HORSE gt lawn amp garden tractors Part No 492 4206 Formerly A 1391 803402 SUPPLEMENT SUPPLEMENT SUPPLEMENT SUPPLEMENTAL INFORMATION INTRODUCTION The following information will assist you with troubleshooting assembly and repair information in light of changes made and experience gained since this manual was first published in 1974 It also contains special service information for 1978 82 model year Sundstrand units SERVICE AND REPAIR PARTS Hydrogear Conversions Many hydrogear units 1966 to mid 1973 have been converted to the serviceable piston piston transmission Refer to the photos in this manual to identify the transmission in a particular tractor Complete Transmissions Complete replacement transmission assemblies are no longer available Independent outside rebuilding service many be available Refer to the latest issue of Service Bulletin 437 for information Repair Parts Use this manual to determine replacement part numbers for 1965 to mid 1973 hydrogear units Pages 54 56 and mid 1973 to 1977 piston piston units Pages 60 62 Be sure to check parts price list to determine if all parts needed are still available before ordering parts Piston piston part numbers for 1978 82 model year tractors are contained in the particular tractor parts manual
30. LL PISTON PISTON HYDROSTATIC TRANSMISSION 1973 1977 e PARTS LIST 1973 1977 PISTON PISTON HYDROSTATIC TRANSMISSION Parts available only through Authorized Dealers When ordering parts always list Part No and Description ITEM PART DESCRIPTION NO NO NO REQ D 1 7877 Pump Shaft Seal 1 2 83 3870 Snap Ring Formerly 200229 1 3 200214 Ball Bearing 1 4 200215 Snap Ring 1 5 200213 Pump Shaft 1 6 200217 Variable Swash Plate 1 7 83 3750 Thrust Plate Formerly 200188 1 8 200216 Pump Housing 1 9 83 3900 Stub Trunnion Shaft Formerly 200236 1 10 83 3890 Control Trunnion Shaft Formerly 200235 1 11 83 3910 Needle Bearing Formerly 200237 2 12 103461 Seal 2 13 103462 Washer 2 14 103463 Retaining Ring 2 15 83 3880 Spirol Pin Formerly 200234 3 16 200239 Cap Screw 4 200219 Cylinder Block Kit Consists of nine pistons and a cylinder block not available separately plus the correct number of items 18 20 21 22 amp 23 18 200212 Slipper Retainer 1 20 83 3920 Washer Formerly 200243 1 21 200244 Spring 1 22 200245 Front Washer 1 23 200208 Retaining Ring 1 24 200220 Valve Plate 1 25 83 3820 Locating Pin Formerly 200198 2 26 200222 Needle Bearing 1 27 200224 Charge Pump Housing 1 28 83 3860 Gerotor Assembly Formerly 200225 1 29 971018 O Ring Large 2 30 103184 Back Up Ring 2 31 200231 Cap Screw Short 2 32 200230 Cap Screw Long 2 33 200226 Socket Head Plug 2 34 83 3850 Pump Gasket Formerly 200223 1
31. RA SEN Cee ee oe EN A ES z T LINDYID LNAWSAIdWN QNV S3ATVA NOILVH313929 V LINIYIJ HOLOIN Q3xid dWfd 318VIHVA FIG 3 DIAGNOSIS This trouble shooting guide has been written to take into account both the most likely causes of service problems and the difficulty of check ing certain parts of the system To save time and expense follow the sequence of steps as outlined in the trouble shooting charts on the following pages When the cause of the problem is found repair or replace the parts involved NOTE Whenever a problem occurs always first check 1 Transmission oil level 2 Speed control linkage page 19 3 The push valve make sure it is closed page 5 SPECIAL SERVICE NOTE If the tractor drives in the wrong direction when the control lever is moved the hydrostatic motor cover was in correctly installed 180 off position by the supplier Turn it to the cor rect position see page 42 step 4 TRACTOR WILL NOT OPERATE IN EITHER DIRECTION ENGINE BOGS DOWN OR STALLS INSPECT INSPECT PARKING INSPECT GEARS HYDROSTATIC OK OK DEFECTIVE JAMMED DEFECTIVE REPAIR OR REPAIR OR REPAIR OR REPLACE REPLACE REPLACE SERVICE AREA GENERAL INFORMATION REMOVAL REPLACEMENT Hydrostatic motor Page 41 Page 25 Parking pawl 2 Page 58 Transaxle gears Page 57 TRACTOR WILL NOT OPERATE IN EITHER DIRECTION TRACTOR CAN BE PUSHED WITH PUSH VALVE CLOSED INSPECT PUSH VALVE NOT
32. SEATED REPAIR OR REPLACE SERVICE AREA Push Valve Motor valve plate Pump valve plate Countershaft keys Speed control linkage Transaxle gears INSPECT HYDROSTATIC VALVE PLATES DEFECTIVE REPAIR OR REPLACE OK GENERAL INFORMATION 5 Page 33 Page 33 s 9 4 w 10 INSPECT TRANSAXLE 7 COUNTERSHAFT KEYS SHEARED REPLACE THEN REPAIR SPEED CONTROL LINKAGE INSPECT MESH OF OUTPUT SHAFT GEAR AND GEAR IN TRANSAXLE OUT OF MESH REPAIR REMOVAL REPLACEMENT Page 43 Page 35 Page 57 db V TRACTOR WILL NOT OPERATE IN EITHER DIRECTION TRACTOR CANNOT BE PUSHED WITH PUSH VALVE CLOSED INSPECT SPEED INSPECT HYDROSTATIC OK CONTROL LINKAGE PUMP SHAFT INSPECT CONTROL SHAFT ROLL PINS DEFECTIVE NOT TURNING BROKEN _ REPAIR OR REPAIR OR SERVICE AREA GENERAL INFORMATION REMOVAL REPLACEMENT Speed control linkage Pogo 17 0 Adua Pump shaft Page 34 Page 37 Control shaft roll pins Page 37 TRACTOR OPERATES IN ONE DIRECTION ONLY INSPECT CONTROL LINKAGE DEFECTIVE REPAIR OR REPLACE SERVICE AREA GENERAL INFORMATION REMOVAL REPLACEMENT INSPECT CHARGE CHECK VALVES INSPECT ACCELERATION VALVES Speed control linkage Page 19 Charge check valves Page 36 Acceleration valves Page 5 Page 40 17 TRACTOR OPERATES ERR
33. a short screwdriver through the hole in the nylon cam and rotate the eccentric cam pin until the rear wheels stop turning This usually occurs at a point midway between forward and backward wheel rotation NOTE The lobe on the eccentric pin must be up for proper operation 6 Retighten the set screw in the arm and replace the access plate w A pw FIG 4 Standard System Neutral Adjustment 1974 Models Only After neutral has been adjusted check to see if the speed control rod is centered in the detent notch of the detent spring This spring is located on the hood stand behind the belt guard The spring incorporates slotted bolt holes so it may be adjusted as required to line up the neutral notch with the control rod FRICTION ADJUSTMENT The speed control lever is friction loaded to hold any selected speed in either direction If the lever does not remain where it is set during operation fric tion may be increased by releasing the lock nut and tightening the collar friction adjustment see Fig 5 This adjustment is made at the front of the seat LOCK NUT NS FRICTION COLLAR ES jon m COLLAR FRICTION ADJUSTMENT FIG 5 Standard Control Lever Friction Adjustment The proper amount of friction is obtained when approximately six pounds of force at the handle moves the control lever Be sure to tighten the lock nut after proper tension i
34. aced They are serviced as a matched set Sticky piston operation can be corrected by lightly polishing the piston and bore of the sleeve with Crocus cloth The piston to bore clearance is extremely close therefore the piston may not pass through the sleeve under its own weight Remove the O rings from the sleeve and discard them Wash piston and sleeve with solvent and air dry them Inspect the springs 4 amp 5 Fig 91 and spring seat 6 for damage and replace if necessary Clean with solvent and dry Coat new O rings with transmission fluid and lightly coat the valves with petroleum jelly Install new O ring seals taking care to avoid nicking their sealing surfaces on screw threads or edges of the valve grooves Press the acceleration valve sleeve 3 Fig 91 over the O ring on the shoulder of the dampening valve 1 Fig 91 The O ring end of the sleeve should be away from the dampening valve Insert the piston 2 Fig 91 closed end first into the sleeve Place the two springs 4 amp 5 Fig 91 in the open end of the piston and push the piston to the bottom of the sleeve Insert the stem of the spring seat 6 Fig 91 in the end of the springs Place the cone 7 Fig 91 in the relief valve seat 8 Fig 91 and bring the open end of the seat and the open end of the acceleration valve sleeve together Install all the parts into the bore of the center section at one time See Fig 93 Tighten
35. arge pump fills the complete system including the area around the ac celeration valves These valves are held open by the spring between them The acceleration valves remain open until high pressure oil is introduced behind one of them Which valve depends on the direction of rotation as determined by the position of the pump swash plate RELIEF VALVES Pressure from 70 to 150 PSI is controlled by the charge pressure relief valve This exhausts the excess charge oil not needed to make up leakage to the oil filter and case reservoir When an implement is used the maximum charge pressure from 550 to 700 PSI is limited by the implement relief valve Some separated systems also incorporate a high pressure relief valve which serves to prolong the life of the hydrostatic unit Located on the left side of the tractor above the transmission this relief valve has been factory adjusted and will reset automatically if triggered FORWARD TRAVEL In forward position the pump variable swash plate tilts and as the cylinder block continues to rotate the pistons cross over a valving plate under low pressure and advance up the swash plate This in turn pushes them into the block forcing the oil from the block under high pressure At the bottom of their stroke the pistons pass again to the low pressure side of the valving plate and are refilled by the charge pump with oil returning from the motor through the low pressure line The high pressure
36. be shims inside the plug to con trol valve spring tension Take care not to lose them Remove and discard the O ring from the plug Check the spring for distortion Replace if damaged Check the nose of the valve for continuous sealing pattern and replace it if damaged Check the seat in the center section for nicks or signs of erosion If it is badly eroded the Hydrogear assembly must be replaced Clean the parts with solvent and coat them with type A automatic transmission fluid Install a new ring on the plug 5 Fig 90 using care not to damage it on the screw threads Install the spring in the valve and inser the assembly valve first into its bore on top of the center section Install the hex head O ring plug and tighten securely Towing Valve If applicable Back out the 1 hex shoulder plug 6 Fig 90 Pull the valve assembly 14 Fig 91 out of the bore The force required will depend on the radial press of the sealing rings on the barrel of the valve Remove and discard the O rings and the Teflon back up ring 13 Fig 91 Clean the valve with sol vent dry and coat with type A automatic trans mission fluid Install the Teflon back up ring 13 Fig 91 in the top groove of the valve Install an ring alongside the back up ring in the same groove on the side away from the valve stem Install the second O ring in the bottom groove From top to bottom of the valve the rings stack up in th
37. dampening valve securely Repeat this operation on the reverse acceleration valve assembly 1 Fig 90 Check Valves Forward and Reverse Remove the reverse check valve O ring plug 4 Fig 90 with a wrench on the hex head Remove the spring 9 Fig 91 and valve 10 Fig 91 using a magnet or long nose pliers if needed Check the spring for distortion Replace it if damaged Remove and discard the O ring from the plug Check the cone for uniformity of sealing pattern A normal cone will have a shiny unbroken circle of contact approximately 4 from the point The seat inside the center section should also be tree of nicks or signs of erosion If the contact pattern is broken the cone should be replaced If the seat is badly eroded the Hydrogear assembly must be replaced Clean the parts in solvent and coat them with type A automatic transmission fluid Install a new O ring on the plug 4 Fig 90 using care not to damage the ring on the screw threads Slip the spring over the shoulder of the valve and install the assem bly into its bore in the center section Install the hex head O ring plug and tighten securely Repeat this operation on the forward check valve assembly 3 Fig 90 SI Charge Relief Valve Remove the 33 hex head ring plug 5 Fig 90 Remove the spring 11 Fig 91 and valve 12 Fig 91 using a magnet to withdraw them from the bore NOTE There may
38. e a small o ring in each of the low pressure port recesses and a large o ring in each of the large high pressure port recesses Then place a square section type back up ring over the top of each of the large o rings centering them as closely as possible To facilitate alignment of the pump to the manifold pad fabricate two aligning pins by cutting the heads off two 35 16 bolts to make two studs each two inches long Saw a screwdriver slot in the end and taper the ends as shown Screw the aligning pins into the 1 F Wi FIG 20 O ring Ports two front threaded holes in the pump pad Install the pump by placing it carefully in position Insert the aligning pins into the front manifold holes as the pump is lowered into place FIG 21 Aligning Pins Allow the pump bracket to rest on the steering gear brace Install punches through the side panel holes and into the front bracket to hold the pump in posi tion Then install the two 3 bolts and nuts and secure the rear pump bracket to the steering gear brace Now install the left panel to the front bracket bolt and nut Connect the hydraulic tubes to the pump fittings Connect the temperature indicator wire to the sending unit FIG 22 Temperature Sending Unit Install the two rear manifold to pump cap screws from underneath Place the elastic stop nuts on top but do not tighten at this time Remove the two FIG 24 Co
39. er is under the head of the front motor to pump bolt 19 2 Examine the motor to case mounting surfaces clean as required and install a new gasket on the motor 3 Place grease around the inside of the strainer flange and insert the strainer into the recess in the transaxle case Make sure the grease holds the strain er in place otherwise the strainer may slip down resulting in a cut gasket 4 With the gasket in place carefully install the pump and motor assembly on the transaxle making sure the cam block pin engages with the cam block so it will not damage the cam block and that the motor sits up flush against the transaxle Secure the assembly at the top with the two 3 case bolts and nuts and the two 38 cap screws at the bottom Tight en all four bolts evenly 5 Install the access plate 6 Install the drive belt on the transmission pulley and install the belt guard assembly 7 Install the footrest bracket 8 Install the tractor seat fender and tool box assembly and retain with the four cap screws 9 Install the left rear wheel and tire assembly 10 Start tractor test and set the neutral adjust ment as required REMOVAL OF HYDROSTATIC UNIT FROM A SEPARATED SYSTEM MOTOR REMOVAL 1 Remove the nuts from the two bolts securing the top section of the motor to the transaxle Remove the two 4 and two cap screws that hold the manifold pad to the motor and tie up the manifold so it will
40. face of the cylinder blocks If the surface is scored replace with a cylinder block kit Pistons and Slippers Scored piston barrels and slippers with edges rounded more than inch must not be used Replace with a new cylinder block kit Slight scratches on slip pers or slightly rounded edges may be removed by lapping Use crocus cloth for finishing Do not remove more than 005 Make sure that all slippers are with in 002 thickness of each other Make sure the lubrication hole is open in the center of the slipper face Use compressed air to open PISTON BARREL SLIPPER RETAINER si ED Slipper Retainers Slipper retainers must be flat Examine them care fully If bent or worn replace them Valve Plates Clean valve plates and check both sides of the plates Remove any burrs or foreign matter from the steel side of the plate Check the bronze side of the plate for scratches and wear This surface must be smooth and free from scratches To check the surface run your fingernail across the plate If wear is felt replace the plate ANCHOR SLOT B 5 VALVE PLATE PUMP MOTOR VALVE PLATE FIG 44 Thrust Plates Inspect both thrust plates for the pump and motor swash plates for flatness scoring and imbedded material Replace as required IMBEDDED MATERIAL FIG 45 Inspect Thrust Plates Charge Pump Assembly Inspect the gerotor set internal and external
41. ine and Hydrogear at low speed to circulate fluid throughout the system and to check for leaks Recheck the fluid level and add as necessary Install belt guard R H foot rest 1968 and 1969 models and the fender seat and tool box assembly Connect tail light if so equipped NOTE To facilitate installation of hydraulic lift hoses see following paragraph leave the tool box assembly loose enough to be shifted at this time If a new Hydrogear assembly is being installed on a fractor which is equipped with a hydraulic lift transfer the implement relief valve from the replaced Hydrogear to the new assembly Fig 97 and con nect the hydraulic hoses Complete the tightening of tool box assembly FIG 97 Install the left rear wheel adjust neutral position at the cam block and install the instruction plate Lower the rear of the tractor to the floor and test operation of the Hydrogear 99 9 MA 2 en 79 0 AN HYDROGEAR PARTS DRAWING 1965 73 Gos ES Si e A ITEM NO HYDROGEAR PARTS LIST 1965 73 Parts available only through Authorized Dealers When ordering parts always list Part No and Description Specifications subject to change without notice PART NO 8046 1532 1533 9416 6449 5959 3915 8047 5960 8050 8051 7202 7203 7169 7199 8053 7196 7200 933209 8056 7235 908138 915663 920009 6452 5963 5964 5965 936131 937014
42. is order Teflon ring O ring O ring Place the washer 15 Fig 91 around the bore in the center section and with a twisting motion insert the valve into the bore Start the hex shoulder plug threads and rotate the valve while drawing it into place with the plug Tighten the plug securely Implement Relief Valve If so equipped Remove the 24 hex head ring plug 7 Fig 90 Remove the spring 16 Fig 91 and valve 17 Fig 91 using a magnet to withdraw them from the bore Remove and discard the O ring from the plug Check the spring for distortion Replace if damaged Check the nose of the valve for continuous sealing pattern and replace if damaged Check the seat in the center section for nicks or signs of erosion If it is badly eroded the Hydrogear assembly must be replaced Clean the parts with solvent and coat them with type A automatic transmission fluid Install a new O ring on the plug 7 Fig 90 using care not to damage it on the screw threads Insert the spring in the valve and install the assembly valve first into its bore on the front of the center section Install the hex head O ring plug and tighten securely Install new oil filter Install the drain plug in the bottom of the transaxle Fill to proper level with type A automatic transmission fluid Approximately four quarts will be required Block the tractor up with the rear wheels off the ground Run the engine at low speed and ope
43. m at the bottom At the top it is connected to the neutral plate so that when the brake pedal is pushed down the control shaft is brought to neutral just as it is when operated by the speed control lever On some models a third rod at the rear connects the neutral plate and the parking brake lever 8 Remove the four X4 cap screws holding the front manifold pad to the pump pad As the two rear screws have elastic stop nuts on the top it will be necessary to hold them while removing the screws An oil drain pan should be placed under this area since there will be some oil loss Where an Allen type screw is used a X hex with a J drive socket is recommended If none is available one can be fabricated by welding a piece of X hex stock to a 3 drive socket 9 Disconnect the hydraulic lift tubes located at the top of the pump from their fittings Discon nect the temperature sending unit wire Remove the two X bolts and nuts that hold the rear pump bracket to the steering gear support After removing the bolt that attaches the front pump bracket to the left side panel the pump and brackets may be removed If a new pump is to be installed carefully change the brackets and linkage from the old pump to the new pump INSTALLATION OF HYDROSTATIC UNIT IN A SEPARATED SYSTEM PUMP INSTALLATION Place a small amount of clean grease in the mani fold plate seal ring recesses and on the seal rings themselves Next plac
44. make a final check of the adjustment at full throttle LEVER POSITION ADJUSTMENT If the speed control lever does not return to the neutral center position when the brake pedal is depressed adjust as follows l Remove the top cotter pin retaining the shift rod 6 44 2 Rotate the shift rod checking periodically until the speed control lever is centered when the brake pedal is depressed 3 Replace cotter pin and washer FRICTION ADJUSTMENT Speed Control Lever A friction adjustment may be necessary on D series tractors if the speed control lever fails to main tain the selected speed l Tighten the nut retaining the rwo friction wash ers 6 14B on the speed control cam 6 12 Ya BW aT x VA VA Va A A 4 PARK BRAKE P ww PRIMARY LEVER MO N NN AG PARK BRAKE fw TENSION ADJUSTMENT PARK BRAKE SECONDARY TRANSMISSION LEVER BRAKE LEVER FIG 9 2 The proper adjustment is achieved when a pull of 24 to 28 lbs is reached measured near the top of the speed control lever FRICTION ADJUSTMENT Parking Brake A friction adjustment may be necessary to main tain the position of the parking brake control in the disengaged position 1 Tighten the nut securing the two friction wash ers 6 43 at the parking brake lever 6 36 Try pushing the tractor both forward and reverse to make sure the parking pawl is fully engaged PARKING BRAKE AD
45. mbly the one with the narrow relief flats together with the spring into the bore at the front of the end cap housing Make sure the spring seats in the spring cavity of each valve When properly seated each valve will have approximately four or five threads exposed so the 78 hex plugs may be easily installed 5 Install both plugs using new O ring seals and tighten securely DISASSEMBLY AND ASSEMBLY OF HYDROSTATIC MOTOR Disassembly of Motor 1 Remove the four 10 24 Allen head cap screws that retain the cover plate and remove the cover plate 2 Remove the large O ring seal from around the ball bearing FIG 71 3 Remove the snap ring from the end of the motor shaft Remove Snap Ring from Motor Shaft AN FIG 72 Hydrostatic Motor Exploded View Centering Pilot Ring Motor End Cap Valve Plate Cylinder Block amp Piston Assembly Thrust Plate Motor Housing p FIG 73 4 Remove the four 16 cap screws that retain the aluminum housing to the motor end cap main iron housing and remove the aluminum housing Note the position of the housing It must be installed with the webbed section up If the cover is reversed the 8 Bearing 9 O Ring 10 Retaining Ring 11 Housing Plate 12 Motor Shaft 13 Motor Shaft Retaining Clip FIG 74 Motor Housing unit will operate in the opposite direction 5 Remove the housing to end cap ga
46. moved they may be pressed out by using a suitable arbor placed against the seal retainer Then press the seal retainer and both needle bearings out the cylinder block side of the end cap Bearing removal and replacement dica FIG 81 Install first Needle Bearing with Seal Retainer Installation Install the first needle bearing into the output end of the motor end cap with the lettered end of the bearing out Press the bearing in to the flush point Then press the seal retainer insert in until it is flush with the end cap I LEAVE 00 EXTEMDCO FIG 82 Instali the second needle bearing into the cy linder block end of the end cap and pressing against the lettered end press it into the hous ing leaving 100 protruding from the face of the end cap To obtain the 100 protrusion try using a 34 cotter pin or washer as a stop for the press For convenience the seal retainer may be pressed in with the bearing Install second Needle Bearing Assembly of Motor 5 Install the motor shaft spring clip with the A rongs toward the output 4 1 Install a new O ring seal in the recess of the Pa DA output shaft seal retainer 6 Apply 10W30 oil on the valve plate surface the cylinder block valving surface and through the valving ports into the cylinder bores 2 Install the aluminum centering pilot on the out put end of the motor end cap and retain with the two l4 cap screws luo R
47. ne end of the motor housing bore Install the other valve in the opposite end Make sure that the spring is seated in the bores of the valves and install the two plugs FIG 36 Acceleration Valves Install two small o rings in the two low pressure ports A third small o ring is installed around the right front bolt hole located at the top left corner of the following photograph Center a square section back up ring on top of each of the large o rings and install them in the two large high pressure ports When properly installed the bottom of the back up rings will be just below the top of the recess r FIG 37 O ring installation Be very careful not to get dirt on the pad surface To install the motor line it up on the two top case bolts Install the nuts on the two lower cap screws Always use a new gasket wmm a L p L E a ___ SE A FIG 38 Motor Installation After the motor has been secured to the transaxle check the seal rings to make sure they are in position Next release the back of the manifold if it was tied up during the motor removal Line it up and install the two 3 bolts and the two 4 bolts Make sure the special seal washer is under the head of the right front bolt T a e 4 1 gt l a nid w KOU n FIG 39 Motor Installation Completed EU ME INSPECTION OF PARTS All
48. ng oil leak at cam block trunnion support casting or serial number plate 80 12 66 Hydrogear Transmission Transaxle usage and interchangeability 1967 and prior 83 1 67 Hydrogear New relief valve spring 7264 relates to tiller installation on earlier units 84 2 67 Hydrogear Oil and filter change recommendation Note Dexron II is present equivalent to Type A Automatic Transmission fluid 101 7 68 Hydrogear Replacement unit installation information 118 12 69 Hydrogear Securing hydraulic valve hoses 437 3 89 Hydrogear Sundstrand rebuilding service Piston Piston Bulletins 172 4 75 Piston Piston Use of rust preventative on axles 174 5 75 Piston Piston Differential bolt diameter change 195 12 76 Piston Piston Motor snap ring failure 1975 and prior tractors S A 105124 217 2 78 Piston Piston Driven coupling installation on D Series tractors 1977 and prior S A 105147 Also see SB 305 252 11 79 Piston Piston Conversion of limited slip to 8 pinion differential 1968 73 tractors S A 105173 Gear 101523 273 5 80 Piston Piston Differential end cap nut 108881 305 4 81 Piston Piston Driven coupling repair procedure D Series tractors 437 3 89 Piston Piston Sundstrand rebuilding service NOTE Service Bulletin information is for repair reference purposes Parts and assemblies covered by bulletin may no longer be available Warranty coverage has expired for all Sundstrand equipped products
49. ntrol Rod Connections aligning studs and install the two front cap screws Finally tighten all four cap screws evenly Connect the three control rods to their respective levers Install the right side panel and battery supports FIG 25 Side Panel Installation Lubricate the pump spline with moly grease and slide the engine carefully to the rear Engage the pump spline with the pump coupling center the engine on the pump shaft and bolt the engine securely to the frame Connect engine controls as required and install and connect the battery Install the grille shroud and hood After checking the oil level filling as required test the unit for proper operation It may be that if the neutral and tension adjustments were disturbed during the operation they will require readjustment p a a 2 LI m L i i i N 3 i i LA FIG 26 Pump Spline Engagement MANIFOLD INSTALLATION Install new seal rings on the front pad as follows Place a small amount of grease in the seal ring re cesses and on the seal rings themselves Place a small o ring in each of the low pressure port recesses and a large o ring in each of the high pressure port re cesses On top of each large o ring place a square section type back up ring Center it exactly on top of each of the o rings 28 FIG 27 Ring Installation Place a protecti
50. on 90 1974 D SERIES TRACTORS NEUTRAL ADJUSTMENT 6 45 L 6 38 22 E 6 42 pe A DA 6 39 iar 6 43 6 24 6 E LT 6 27 y ns NOY DD T 6 37 d 6 26 6 28 FIG 8 Brake Speed Control Linkage 1974 D Series 21 5 If the parking brake lever is loose in the dis engaged position adjust the length of the transmission brake lever rod until there is little play left before it begins to engage 1974 D SERIES TRACTORS NEUTRAL ADJUSTMENT FIG 8 1 Block the rear wheels off the ground 2 Depress the brake pedal item 6 20 and keep it depressed during adjustment 3 Loosen the set screw 6 11 Start the engine and run it at half throttle 4 Adjust the eccentric 6 09 until true neutral is reached Check this by making certain the tires have stopped rotating Be sure to check both tires This usually occurs at a point midway between forward and backward wheel rotation 5 Retighten the set screw 6 Move the speed control lever into forward and reverse several times depressing the pedal each time 1974 D SERIES TRANSMISSION CONTROL LINKAGE NEUTRAL ADJUSTMENT ECCENTRIC NEUTRAL PEDAL CONTROL 2 6 fp NEUTRAL 4 RETURN FORWARD REVERSE LEVER LEVER TENSION ib ADJUSTMENT 2 PUMP CONTROL SHAFT to make sure of the neutral setting Then
51. ons during every step of the Hydrogear tune up Instead of repeating a cleanliness precaution throughout these instructions this note at the begin ning is intended to emphasize its importance Exer cise the utmost care at all times to prevent the intro duction of dirt clippings or any other foreign matter into the hydraulic system Remove the fender and tool box assembly to expose the center section of the Hydrogear as shown in Fig 90 Thoroughly clean the center section of all dirt clippings etc with a solvent that is not harmful to paint Remove the drain plug at the bottom of the transaxle case and drain the fluid Remove the oil filter for replacement FIG 90 Prepare a clean work area for inspecting the highly polished surfaces of the valves to be serviced The parts to be removed are manufactured to close tolerances and are very critical to the proper opera tion of the Hydrogear Handle them with care to avoid damage to the sealing surfaces Acceleration Relief Valves Remove the forward dampening valve item 2 Fig 90 with a 1X wrench on the hex head Occasionally the acceleration valve piston and sleeve assembly 2 amp 3 Fig 91 remains on the dampening valve when removed When this happens separate them for inspection and cleaning If the piston and sleeve remained in the bore re move the piston 2 Fig 91 two springs 4 amp 5 Fig 91 spring seat 6 Fig 91 and relief valve cone 7 Fig 91
52. op of each of the large O rings making sure they are centered exactly over the rings see Fig 18 3 Carefully mate the pump to motor using the bolts for alignment so the units will not have to be shifted once they are together Shifting could disturb the seals and leaks may result 4 Make sure the copper seal washer is placed under the head of the right side motor to pump bolt right side means as viewed looking at the motor and the transaxle gasket surface Proper placement of this washer will assure that internal leaks will not occur in this area when the motor is bolted to the transaxle Fig 19 5 Tighten all four bolts evenly REMOVAL OF HYDROSTATIC UNIT FROM A STANDARD SYSTEM l Remove the left rear wheel and tire assembly 2 Remove the tractor seat fender and too box assembly 3 Remove the foot rest bracket 4 Remove the belt guard and remove the drive belt from the transmission pulley 5 Remove the access pump 6 Remove the two bolts and nuts at the top of the assembly and the two cap screws on the bottom Carefully remove the pump and motor assembly from the transaxle making sure the cam block pin disengages from the cam block Remove the old gasket and all traces of dirt and oil INSTALLATION OF HYDROSTATIC UNIT IN A STANDARD SYSTEM 1 Make sure the shipping plugs have been moved and that the motor to pump and pump to motor bolts are tight Also make sure a copper wash
53. oper understanding of the Wheel Horse automatic transmission The automatic transmission is a sophisticated piece of machinery Maintain strict cleanliness control during all stages of service and repair Even a smali amount of dirt or other contamination can severely damage the system Although this manual deals primarily with the Sundstrand piston piston type hydrostatic transmission service and repair procedures for the older hydrogear type transmission have been included in a separate section Hy w it gt ___ _____ 1 PRINCIPLES OF OPERATION Relief Valves DIAGNOSIS rene TROUBLE SHOOTING CHARTS SPEED CONTROL LINKAGE AND ADJUSTMENTS Standard System Neutral Adjustment Friction Adjustment SPEED CONTROL LINKAGE AND ADJUSTMENTS Separated System 1973 18 HP Automatic Neutral Adjustment Friction Adjustment assaasanssase Parking Brake Adjustment 1974 D Series Tractors Neutral Adjustment Lever Position Adjustment Speed Control Friction Adjustment Parking Brake Friction Adjustment Parking Brake Adjustment 1975 D Series Tractors Neutral Adjustment Lever Friction
54. otal of five quarts on most tractors six quarts on D series tractors Normally one quart is retained in the hydrostatic unit leaving four quarts to be added Run the tractor for a minute then check oil level Add oil if necessary Use only 10W30 automotive engine quality oil TRANSAXLE GASKET INSTALLATION 1 Block the tractor under the frame 2 Loosen the lock nut and set screw on the right hand side and remove the entire tire wheel and hub assembly Remove the woodruff key and file any rough edges from the key slot and the end of the axle 3 Remove the tractor seat and fender assembly by removing the hardware holding it to the transaxle Remove the footrest bracket and the belt guard as sembly and remove the drive belt from the trans mission Remove any access plates 4 Disengage the spring from the parking brake Remove the rear hitch 5 Remove the two cap screws holding the right half of the transmission case to the frame 6 Remove the six nuts from the bolts holding the transmission halves together Do not remove the bolts securing the hydrostatic unit FIG 104 Transmission Half and New Gasket 7 Slide the transmission half off the axle Care fully clean all machined surfaces of dirt Take care to keep any foreign matter from entering the system Replace the gasket 8 Carefully reinstall the transmission half to pre vent damage to the axle seal Tighten all nuts securely in rotation
55. ove the fan guard and fan on 1965 1966 and 1967 models On 1968 and 1969 models remove the belt guard To do this it will also be necessary to remove the R H foot rest on these models Loosen the belt tension by setting the parking brake and remove the belt from the shaft pulley Remove the pulley and Woodruff key from the input shaft NOTE It is extremely important not to damage the shaft or the soft aluminum housing The follow ing steps should be done very carefully Slide a small hook tool or screw driver along the shaft into the lip seal Tip the tool until it contacts the outer metal edge of the seal and pry outward gently Change position of the tool and repeat the process until the seal has been worked out of the housing Discard the seal Inspect the shaft and polish out any nicks or burrs that could cut or damage a new seal Do not let any particles enter the pump Coat the sealing lip with automatic transmission fluid and slide the seal over the shaft Align the seal to the aluminum housing A thin coat of gasket shellac on the seal O D will aid in sealing the steel seal to the pump housing Place a tool approximately the size of the seal O D over the metal face of the seal the input pulley hub can be used and press the seal into the housing until the seal is flush with the edge of the housing Check oil level and replenish as necessary Align and install the pulley belt and fan if so equipped Install
56. parts should be thoroughly cleaned and exam ined After examining cover all parts with a lint free cloth while waiting for assembly Oil all moving parts with 10W30 premium engine oil when assembling MARINS SURFACES MOTOR SHAFI most SHAFT SEAL AREA FIG 40 Pump and Motor Shafts Examine the bearing and seal surfaces of the shafts Scored or worn shafts must be replaced Pay particular attention to the pump shaft seal area A scratched seal area will cause an oil leak Cylinder Block Assemblies General Although the pump and motor cylinder block and piston assemblies look similar they differ Two cylin der block kits one for the pump and one for the motor are available and should be used for replace ment when the following conditions are found TOD APPIR FACEM MOOR ASTON FIG 41 1 Cylinder bores out of round or scored 2 Cylinder block face valving surface worn scratched or scored 3 Scored piston barrels 4 Slipper edges rounded more than inch When inspecting cylinder block assemblies always return pistons to their original cylinder bores FIG 42 Check Free Movement of Pistons Check to make sure the pistons move freely in their bores Carefully remove each piston and check for scores on the piston barrels and on the cylinder bore walls Replace with cylinder block kit if bores or barrels are scored Cylinder Block Face Inspect the polished valving sur
57. pass or flow from one side of the main circuit to the other When pushing the motor becomes a pump forcing the oil through the open valve and to the other side of the motor The direction of oil flow depends on the direction the unit is pushed NOTE On B and C series tractors and similar prior models the hydrostatic pump and motor are bolted together as a single unit For purposes of description we will refer to such a transmission system as a standard system On D series tractors and similar prior models the pump and motor are separated in corporating a manifold between them In this manual we refer to such a system as a separ ated system NOI LISOd IVaeLnNaAaN uUOISSIUISUBJ 21303504p AH UO3SI UOJSIJ MIOAYISIY 3H3HdSOWAV e omm B An LA 1 1 IRA A 031113 39055399 ISVI 390553994 3YNSSIYUA JIOUVHI Sy 5i E3 ANO14 NOMINS INIVAYIS ASTRO N a Vi BAS d m 5555555 X 2 1 YOLOW LN3WIIVIdSIO mE D sac vA 2222222 222222 va Z IN3WIIVIdSIO 318VINVA d oniwa 5 7 NAN LIVHS t M 104100 di 7 mwenn AN dine Ed OC Je Wer 2 222 2 47 da D LO PEL ER NZ LS H Vh SON tb EC 45 414 D d dwn ABOLITO I 7 4 e af v a k a
58. ph shows the front of the manifold as it is inserted past the steering gear bracket turned to position it for attachment to the pump pad Leave the protective cover on this pad while the rear of the manifold is being connected to the hydraulic motor FIG 31 Rear Manifold Pad in Place 20 Carefully hold the manifold in place Align the bolt holes in the manifold pad with the bolt holes in the motor and install all four bolts Make sure that the special seal washer is under the head of the right front 4 bolt Do not completely tighten the bolts at this time Just leave them snug so that the front of the manifold may be aligned without distorting the tubes Remove the protective cover from the front manifold pad and check to make sure all seal rings are in place This can be done by flexing the tubes down just enough to feel if all the o rings and back up rings are in place Position the manifold pad so the bolt holes line up and install the two short front hex screws Leave them loose at this time Install the two longer bolts in the two rear holes with the elastic stop nuts on top Tighten al four bolts evenly holding the nuts on the rear bolts as required Now tighten all four of the rear manifold pad to motor bolts FIG 32 Manifold Installed Install the seat spring on its support and install the spring block on top of the spring mas FIG 33 Spring and Block Install the seat pivot assembly Insert
59. ps with 10W30 engine oil 4 insert the swash plate assembly into the case Slide the trunnion shafts into each side and into the swash plate housing Line up the roll pin holes and install the roll pins One roll pin is used at the short trunnion shaft and two roll pins are used at the con trol shaft Drive the first pin in so it enters into the far side of the swash plate Then drive the second roll pin down against the first pin until it is 14 below the surface of the swash plate Drive the single roll pin at the short trunnion side so that it is 14 below the surface See Fig 57 5 Install the trunnion seal washers and the retain ing rings 6 Install the pump shaft by tapping it through the bearing from the inside and retain it with the external snap ring 7 Lubricate the pump shaft seal and install over the pump shaft with the lip side toward the pump Press it in place so that it is flush with the outside of the housing Assembly of Pump Section 1 Install a new O ring seal and new back up ring on the free wheeling valve making sure the seal is toward the pump housing and the split back up ring is toward the outside Install the valve assembly LU gt CU meo FIG 60 Pump End Cap Valves 2 Install both pump check valve balls and springs together with their slotted plugs and O ring seals 3 Viewed from the motor side of the pump end cap install charge relief valve and implemen
60. r uw CS POINTS FIG 14 Charge Pressure Test Standard System PRESSURE PORT IMPLEMENT PRESSURE TEST Ta yn Use the same gauge hook up as Charge Pressure Test if the tractor is equipped with a hydraulic lift im plement pressure should be checked Pressure should SECTION Oe MOTOR HOURS wT FACE UP hii BL Y FIG 17 Separation of Pump and Motor The pump and motor may be separated so that new FIG 15 Hydrostatic Transmission seal rings may be installed between the pump and the As installed in a Standard System motor housings and to facilitate overhaul Four bolts fasten the two units together Two of the bolts are accessible from the top and go down through the pump into the motor housing The other two are ac cessible from the gasket side of the motor where it attaches to the transaxle and go up through the motor into the pump housing Because Allen type screws are used a X inch hex Allen wrench is required Seal Ring Installation amp Assembly of Pump to Motor 1 Place one small O ring in each of the two low pressure ports and one at the corner bolt hole that is counterbored to accept an O ring see Fig 18 FIG 18 NIAI CC SEAL WASHER MERE FIG 19 2 Place a large O ring in each of the two high pressure ports and then place a square section back up ring on t
61. rate the Hydrogear in forward and reverse to circulate fluid through the system and to check for leaks Recheck the fluid level and add as necessary Adjust neutral position Lower rear wheels to the ground Reinstall the fender and tool box assembly Run the tractor to thoroughly test operation of the Hydrogear HYDROGEAR REMOVAL AND REPLACEMENT Removal If the transmission has been contaminated either with metal filings or other foreign matter the fluid must be changed and the oil filter replaced The transaxle must also be flushed thoroughly before a new Hydrogear assembly is installed Support rear of tractor with rear wheels off the floor Remove the left rear wheel If tractor has tail light disconnect wire and bring it forward of the tool box If the tractor has a hydraulic lift disconnect the hoses from the Hydrogear and move them for ward out of the way Remove the instruction plate located in front of the seat by removing four mount ing screws Remove the four tool box to transmission bolts and remove the fender seat and tool box as an assembly NOTE On 1965 1966 and 1967 models it is also necessary to remove the fan guard The 1968 and 1969 models will also require the remova of the two belt guard to tool box bolts Remove the belt guard and drive belt To do this on 1968 and 1969 models the R H foot rest must be removed Remove the cooling fan from the drive pulley if so equipped and remove the pulle
62. rotors and the housing for wear and scoring Replace as required Note The gerotor set is a matched unit Always replace as an assembly If the charge pump housing is worn or scored it must be replaced Bearings for replacement see Disassembly and Assembly section Examine the needle bearings in the pump and motor end caps and replace as required Examine the ball bearings in the pump and motor housings and replace as required BA SS FIG 46 Hydrostatic Pump Exploded View 1 Pump Shaft Seal 11 Gerotor Set 2 Shaft Retaining Ring 12 Pump End Cap Housing 3 Bearing 13 Retaining Ring 4 Bearing Retaining Ring 14 Retaining Washer 5 Pump Housing 15 Trunnion Shaft Seal 6 Swash Plate 16 Trunnion Shaft 7 Thrust Plate 17 Roll Pin 8 Cylinder Block amp Piston Assembly 18 Trunnion Shaft Needle Bearing 9 Valve Plate 19 Control Shaft 10 Charge Pump Assembly 20 Pump Shaft 1 Remove the four 16 socket head cap screws DISASSEMBLY amp ASSEMBLY OF that hold the finned aluminum pump housing to the HYDROSTATIC PUMP 2 With the pump assembly held horizontally carefully remove the finned aluminum pump housing together with the input shaft swashplate and cylinder block assembly Note Make sure the cylinder block and piston assembly does not drop off the input shaft The valve plate may stick to the cylinder block and come out with it or it may stick on the charge pump housing 3 Remove
63. runnion shaft retaining rings and washers Drive the stub trunnion shaft in from the outside and remove Drive the control shaft out from the inside using a long punch inserted through the removed trunnion shaft hole 7 Remove the swash plate housing 8 Pry out the trunnion seals being careful not to damage the housing Note If examination of the trunnion shaft needle bearings and the pump shaft ball bearing shows them to be in good condition steps 9 and 10 should not be performed 9 Using a suitable arbor such as a socket press or drive needle bearings out of the housing from the inside reg og umn Needle Bearing Removal SS 10 With snap ring pliers remove the internal re taining ring that retains the pump shaft ball bearing in the pump housing then remove the bearing by press ing it toward the inside of the housing Assembly of Pump Housing 1 Install pump shaft ball bearing in the front of the pump housing and retain with the internal tru arc retaining ring 2 Note Only if needle bearings have been re moved install the two trunnion shaft needle bearings from the outside pushing on the lettered end of the bearing The bearings should be pressed in flush with the bottom of the seal bore so they will not interfere with the seal installation FIG 59 Needle Bearing Installation 3 Install new trunnion shaft seals pressing them in until they touch bottom Oil the seal li
64. s achieved The friction collar is self lubricating and does not require lubrication SPEED CONTROL LINKAGE AND ADJUSTMENTS Separated System 1973 18 HP AUTOMATIC NEUTRAL ADJUSTMENT An access hole is provided in the right console panel for the neutral adjustment LOCE SCETW FRICTION ADJUST MENT FIG 6 18 HP Automatic Adjustments If the tractor creeps when in neutral adjust as follows 1 Block the rear wheels off the ground 2 Loosen the lock screw holding the eccentric assembly see Fig 6 3 Depress the brake pedal and keep it depressed during adjustment 4 Start the engine and run at half throttle Dis engage the parking brake Insert a screwdriver _ Foi 1973 18 HP AUTOMATIC SPEED CONTROL ADJUSTMENT TRUNNION ECCENTRIC SS NEUTRAL ADJUSTMENT ECCENTRIC TRANSMISSION CONTROL LINKAGE NEUTRAL POINT OF NEUTRAL 5 PARK BRAKE da a oma 1 4 CONTROL LEV ki e Le ARM cn 4 w L SPEED CONTROL ARM ia S tension MOUSE S 69 PARK BRAKE 5 NEUTRAL p ADJUSTMENT NUT RETURN Ane PT 2 lt NEUTRAL R A OUT PEDAL REVERSE EA A fs FORWARD O 9 ECCENTRIC PLATE e wi PUMP NEUTRAL ADJUSTMENT 5184 gt CONTROL LA G k PUMP CONTROL 9 r ARM j PARK BRAKE ADJUSTMENT NUT 1a y TO
65. sket 6 Remove the thrust plate from the fixed swash plate in the housing 7 Remove the ball bearing from the aluminum housing 42 FIG 75 8 Remove the two 14 cap screws that fasten the aluminum pilot centering ring to the motor end cap and remove the pilot 9 Place the end cap cylinder block and motor shaft assembly in a press making sure the cylinder block and valve plate are seated on the end cap housing k Press Motor Shaft to release Retaining Clip FIG 76 10 Press on the motor shaft until the motor shaft retaining spring clip pops loose from the retainer in the center of the cylinder block This pressing opera tion only requires moving the shaft a short distance CAUTION Do not press the shaft through the cylinder block at this time 11 Remove the assembly from the press and re move the cylinder block FIG 77 Remove Spring Retaining Clip 12 Remove the spring retaining clip from the motor shafi 13 Remove the motor shaft from the end cap housing at s tits MA FIG 78 14 Remove the motor valve plate a dU FIG 79 Remove Seal Retainer Ring 15 Remove the O ring from the seal retainer insert at the output end of the motor end cap LI E den e Z FIG 80 Remove both Bearings and Seal Retainer 16 A Removal If the motor end cap bearings are to be re
66. slotted pump check valve plugs together with their respective check valve balls m LEAVE Heo EJ yo ka SUM 4 a Pe M FIG 54 Needle Bearing Installation b To install the needle bearing press it in place from the front side Note Always install needle bearings pressing on the heavy end which may be easily identified It is the end where the identification numbers are found Press bearing to the correct depth 100 should be FIG 53 Needle Bearing Removal left out of the bore 3896 PUMP HOUSING DISASSEMBLY amp ASSEMBLY Disassembly 1 Remove the thrust plate from the swash plate assembly FIG 55 Seal Removal 2 Remove the pump shaft seal a Use a sharp awl and puncture the seal retainer b Pry out the seal being careful not to scratch or damage the shaft seal surface or the aluminum housing 3 Using snap ring pliers remove the retaining ring from the shaft THELIST PLATE PLATE FIG 56 4 Remove the shaft by tapping on the input both ends are splined end and pushing it through the bearing SWASH PLATE CROSS SECTION CONTROL SHAFT WU ANNO Sha STUB SHAFT 5 Using X4 punch drive the swash plate to trunnion shaft roll pins out toward the closed end of the case Note One roll pin is used at the short stub shaft and two roll pins are used at the control shaft 6 Remove the t
67. ss filings on the valves and the passages usually indicates internal damage to the pump or motor section of the Hydro gear This is also true if there is evidence of severe contamination from an outside source Because com plete disassembly would be necessary to repair such damage or to clean out the contaminate replacement of the complete Hydrogear assembly is advised Moderate contamination can be flushed out through the valve ports with solvent The most critical area of the acceleration relief valve is the dampening valve portion 1 Fig 91 Remove the O rings and discard them Clean the valve thoroughly with solvent and inspect for visual damage If there are indications of damage to the pin or ball or if the valve rattles when shaken re place the dampening valve assembly Inspect the relief valve cone 7 Fig 91 and mating seat 8 Fig 91 for damage Check the cone for uniformity of sealing pattern Normal cones will show a shiny unbroken circle of contact approxi mately 32 from the point Similarly the mating seat should be free of nicks or signs of erosion If the pattern is broken or the seat damaged the cone and seat should be replaced Remove O ring from the seat and discard Clean the parts thoroughly with solvent and let them air dry Next examine the acceleration valve sleeve 3 Fig 91 and piston 2 Fig 91 for scoring or sticky operation If either part is severely scored both must be repl
68. t is used on boih sides of the pump housing Fig 57 Using a later transmission on an earlier tractor may require cutting a clearance hole in the tractor s sheet metal for the longer shaft Acceleration Valves Original equipment valves are different Fig 68 and must not be exchanged during repair However the forward valve is used as the service replacement part for both locations If an acceleration valve seems to be malfunctioning ensure the metering plug hole is open Fig 70 If clogged it will prevent the valve from closing The hole is extremely small and it may take a magnifying glass to see it Motor Section Note that the webbed section of motor housing must be up Fig 74 or motor will run opposite the intended direction Special Assembly Note Ensure you use new retaining parts in the motor section Items 23 70 73 74 Pages 61 62 to ensure the integrity of the cylinder block attachment to the motor shaft On assembly make absolutely sure the cylinder block is locked securely on the motor shaft Be sure the notch in the valve plate is over the dowel pin in the motor end cap Supplement 3 FOREWORD This service and repair manual has been compiled to provide authorized Wheel Horse service personnel with the proper procedures and techniques for servicing Wheel Horse automatic transmissions The following index lists all areas covered It is advisable to read all of the introductory sections first to gain a pr
69. t valve parts Pi RISE VALVE EQUIPRED WITH HEX PLUG OHLY j s 4 o CHARGE VALUE WT ET ker MAA LET FIG 61 Pump End Caps a Models not equipped for hydraulic lift 1 Install the hex head plug and new O ring seal in the top left corner of the pump end cap 2 Install the cone valve charge valve spring together with the hex head plug and new O ring seal in the top right corner of the pump end cap b Models equipped for hydraulic lift 1 Install the X ball valve and spring to gether with the hex plug and O ring in the top left corner of the pump end cap 2 Install the cone valve and spring in the top right corner of the pump end cap then making sure that the original shim pack is in the spring cavity of the plug install the plua ring and shim assembly SEAL RING GROOVES FIG 62 Charge Pump Assembly 4 Install the gerotor set in the charge pump hous ing and install the pump housing and gerotor assem bly on the pump end cap using new seal rings rings and back up rings with the valve plate dowel pin toward the bottom Install the two long and two short bolts and tighten evenly FIG 63 Charge Pump Housing 5 Install the valve plate on the charge pump housing centering it around the needle bearing with the steel face of the plate against the charge pump housing and the slot over the dowel pin
70. the end cap housing NARROW FLAT REVERSE VALVE WIDE FLAT FORWARD VALVE FIG 68 Acceleration Valves 40 1 Remove the 78 hex head plug from each side of the motor end cap Gat in man ms oom L cc Res e lt ax amp 5 wb oe cm 04 7 2705 a fs vas PV eee s B FIG 69 2 Remove the first valve by pulling it out Remove the second valve by pushing it out withthe spring and remove the spring NOTE To simplify removal of the forward valve located at the rear of the end cap housing move the tractor about an inch and oil pres sure will force the valve to pop out AR MAKE SURE THE SuLALL FLUG ORATE MOLE OS THE MITERING FLLIG CUS FIG 70 3 The acceleration valves may be disassembled for inspection and cleaning Disassembly a Carefully hold the valve body wrapped in a cloth to protect it Remove the metering plug ball and spring Assembly Important a Make sure the small metering plug orifice in side of the metering plug is open Fig 70 b Seat the ball in the end of the metering plug and install the spring and metering plug 4 Install the forward acceleration valve assembly the one with the wider relief flats in the bore at the rear of the end cap housing Insert the reverse acceleration valve asse
71. the pump housing pump end cap gasket 4 Carefully slide off the cylinder block and piston assembly from the pump shaft Important If any of the pistons slip out return them to their original cylin der bores Place the cylinder block and pistons on a lint free towel so the valving surface and slippers will not be damaged If the pump housing is to be FIG 47 Pump Housing Removal disassembled to remove the shaft trunnion or swash lia plate refer to the Pump Housing Disassembly and Assembly section CHARGE PUMP HOUSING VALVE PLATE FIG 48 Charge Pump Housing With Valve Plate HOUSING BOLTS FIG 49 Charge Pump Housing Valve Plate Removed 5 Remove the valve plate from the charge pump housing noting that the steel surface fits against the charge pump housing and over a dowel pin to keep it from rotating 6 Using a 3 12 point socket remove the two short and two long 3 24 charge pump housing to end cap bolts GEROTER FIG 50 Charge Pump Assembly 7 Remove the charge pump assembly from the pump end cap being careful to keep the gerotor set together Carefully note the position dowel pin down of the charge pump assembly in relation to the end cap S bat lad vA WE CHARGE Val VT m WITHOUT FIG 51 Pump End Caps 8 Remove the hex plug from the top left corner of the pump end cap Top left means viewed from the mo
72. to keep it from turning Mounted properly the plate should be flush against the housing so the cylinder block will operate on the bronze surface CHARGE PUMP HOUSING VALVE PLATE FIG 64 Charge Pump Housing With Valve Plate 6 Install a new pump housing to end cap gasket on the pump end cap WASH PLATE FIG 65 7 Apply oil to the thrust plate and place it on the swash plate ee PETOR SLPPES FIG 66 8 Lay the pump end cap on a flat surface and install the cylinder block with the piston and slipper assembly on the valve plate 9 Center the charge pump gerotor drive so the pump shaft and spline can enter it Pump Housing Installation 10 Making sure the control shaft is on the correct side carefully install the aluminum pump housing and shaft so the shaft spline enters the cylinder block and gerotor drive Install the four pump housing cap screws to align the pump gasket and end cap Push the pump housing in place it may be necessary to turn the pump shaft to align it with the charge pump spline After the housing and shaft are pushed in place tighten the four bolts evenly REMOVAL amp REPLACEMENT OF ACCELERATION VALVES NOTE Although the acceleration valves look similar they are not alike The forward valve located at the rear of the end cap housing incorporates wider relief flats on the valve lands than does the reverse valve located at the front of
73. tor side of the end cap See Fig 51 If the unit is equipped for hydraulic lift operation re move the charge ball valve and spring from the pump end cap top view If the unit is not equipped for hydraulic lift operation there will be no spring and ball valve in this area bottom view m and springs These valves are located in the passage just below the charge and implement valve passage 11 Remove the push or free wheeling valve by unscrewing it from the housing 12 Remove the split back up ring and the O ring seal from the valve 13 If the needle bearing in the charge pump housing is damaged replace as follows Using 1 flat washer with two opposite HALE _ edges ground to a width of 1 as a tool in sert it from the gerotor side against the inside of the needle bearing Then pressing against the washer with an arbor remove the needle bearing FIG 52 Pump End Cap Valves 9 Remove the hex plug from the top right corner of the pump end cap Viewed from the motor side of the pump end cap see Fig 52 If the unit is equipped for hydraulic lift operation there will be shims located in the spring cavity of the plug Do not lose these shims as they determine the amount of implement pressure Remove the spring and cone valve Do not mix up this implement valve spring with the charge valve spring removed from the top left corner 10 Remove the two
74. tral position of the console slot depress the brake pedal and adjust the length of the shift rod arm by rotating it in its trunnion LEVER FRICTION ADJUSTMENT The speed control lever is friction loaded to hold selected speed in either direction If the lever does not remain where it is set during operation the friction may be increased by tightening the adjusting nut through the access hole located in the right panel Fig 10 The proper amount of friction is obtained when approximately 18 pounds of force at the handle moves the control lever PARKING BRAKE ADJUSTMENT 1 With the engine shut off press and release the brake pedal 2 Engage the parking brake by placing the lever in the top slot of the console panel 3 Check the need for adjustment by moving the speed control lever back and forth to determine if the linkage can be moved from neutral toward either the forward or reverse positions FIG 11 Parking Brake Adjustment 4 If the speed control lever be moved toward either position shorten the length of the park ing brake arm assembly rod see Fig 11 by turning the nut against the trunnion 1975 D SERIES W t 9 R k REVERSE FIG PRESSURE TESTING Use a 0 to 1000 gauge for all pressure testing Block the rear axle so the wheels are off the floor All pressure testing should be performed at or near full throttle with the wheels turning Turn the wheels by moving
75. ur nuts and bolts from the differ ential assembly The unit may now be separated allow ing the replacement of the bull gear pins pinion gears or the differential cases Note the position of the pinion gears Adjacent pinions are installed in opposite directions teeth up or teeth down There fore the positions of diagonally opposite pinions are the same see photo FIG 102 Pinion Gear Placement 10 The axle gears may be separated from the axle by removing the snap ring NOTE During re assembly tighten all bolts securely in sequence PARKING BRAKE AND OIL FILTER 1 To replace the oil filter remove by turning counter clockwise This throw away filter should be replaced every year or every 100 operating hours PASO LEME FIG 103 Side View Showing Filter and Parking Brake 2 To remove the parking brake lever drive out the roll pin using a punch Slip the brake lever off the shaft 3 Remove the parking pawl from inside the trans mission case NOTE During reassembly the parking pawl should be pointing toward the rear and the parking brake lever toward the front when installing the roll pin BB CAUTION NOTES For proper operation it is vitally important to keep the interior of the transmission as free of dirt and foreign matter as possible Exercise caution when servicing the unit to prevent damage to oil seals bearings and other internal parts Transmission oil capacity is a t
76. ve cardboard cover over the seal rings to hold them in place and keep the area free from dirt during installation FIG 28 Protected Seal Rings The following photograph shows the location of the seal rings and manifold attaching bolts at the hydraulic motor pad NOTE Two 2 bolts and wash ers are at the left side of the pad and two 14 bolts at the right side Also note that the rear 14 bolt does not use a washer The front 15 bolt however requires a special seal washer Also an o ring is used at this corner between the manifold and the motor pad These extra seals are required since this bolt goes down into a pressure area If it is not sealed there will be a major oil leak Before installing seal rings place a small amount of grease in each recess and on all seal rings Place one small o ring in each of the two low pressure ports and one at the right front bolthole recess Place a large o ring in each of the high pressure ports and then place a square section back up ring exactly over the top of each of the large o rings Make sure no dirt or foreign matter falls into this area while installing the manifold Prior to installing the manifold examine it care fully for cracks around the tubing welds and make sure the clamp prevents the tubes from flexing If the tubes can be moved in the clamp remove the clamps FIG 29 Ring and Bolt Locations and shape them as required to hold the tubes firmly The following photogra
77. y Clean all dirt and clippings off the Hydrogear and surrounding area with solvent and compressed air to keep the interior of the transaxle free of foreign matter when the Hydrogear is separated from the transaxle Place a drain pan beneath the Hydrogear FIG 94 Remove three cap screws and two nuts which secure the Hydrogear to the transaxle Fig 94 Slide the Hydrogear rearward to disengage the cam block pin from the cam block and lift the assembly off the transaxle Fig 95 FIG 95 Remove the strainer Fig 96 and clean with sol vent and compressed air The strainer contains a magnet to retain metal particles circulated by the fluid Installation Clean the gasket surface on the side of the trans axle Make sure the strainer is in place in the trans axle Coat the gasket surface with petroleum jelly to hold the gasket in place and position a new gasket on the Hydrogear If a new Hydrogear assembly is being installed remove the plastic plugs from the inlet and outlet ports of the new unit Position the Hydrogear assembly on the transaxle with the cam block pin engaged in the cam block Start three cap screws and two nuts on the through bolts and tighten until snug Then in rotation tighten the nuts and screws securely FIG 96 Reinstall and align the pulley fan if so equipped and drive belt Fill the reservoir to proper level with fresh type A automatic transmission fluid Run the eng
78. y one of the other conditions listed Normal temperature 180 degrees F 5 Transmission noisy noise may issue from either the Hydrogear or the transaxle PRELIMINARY CHECKS Make it a practice in every case to perform the following preliminary checks They will pinpoint some easily overlooked items and save the time and ex pense involved with unnecessary teardown 1 Check oil level in reservoir and replenish if necessary 2 Check control linkage to make sure it is prop erly connected and operates normally 3 Close towing valve and try to push the tractor If the tractor can be pushed a malfunctioning valve is usually indicated 4 Make sure the tractor can be pushed with the towing valve open lf it cannot be pushed there may be a valve malfunction seized gear motor or transaxle failure 5 Check drive belt condition and fit Make sure parking brake operation is normal 6 Check for oil leakage at operating shafts gasketed joints filter base etc Replace gaskets and seals as necessary 7 Check and correct air cooling fins clogged with dirt or clippings or other apparent damage or trouble causing condition The trouble shooting chart indicates possible causes and test or corrective procedures for the five trouble conditions listed above The Hydrogear Tune Up pro cedures are recommended as a correction in several cases HYDROGEAR TUNE UP CAUTION Cleanliness is one of the most important considerati

Sundstrand Model 90

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