Rebuilding Automatic Transmissions and Transaxles
Contents
1. All of the following tools can be used to remove the front pump from the transmission case except A a special puller B a slide hammer C a hammer and punch D a pry bar If the air bleed check ball is missing from the clutch piston what should the technician do to correct the problem A Replace the clutch apply piston B Install an old valve body check ball in the bleed hole C Block off the bleed hole with a small screw D Block off the bleed hole with an oversize check ball Technician A says that new friction discs should be soaked in clean transmission fluid before being installed Technician B says that compressed air is used to check clutch pack clearance Who is right A A only B B only C Both A and B D Neither A nor B A drum with a slightly worn band apply surface should be A turned on a lathe B sanded front to back B C sanded around its diameter D replaced Automatic Transmissions and Transaxles The usual reason for servicing band servos is to replace A springs B pistons C seals D snap rings Technician A says a one way clutch that turns in both directions can be reused Technician B says a one way clutch showing any signs of wear should be replaced Who is right A A only B B only C Both A and B D Neither A nor B Transmission endplay may be corrected by replacing the A case gaskets B2. C thrust washers D needle bearings snap rings Atransmission has been rebuilt The output shaft turns easily but the input shaft does not turn Technician A says that this is a normal condition when any bush ings have been replaced Technician B says that both shafts should turn freely Who is right A A only B B only C Both A and B D Neither A nor B Operation on the stator one way clutch A can be checked by applying air pressure to the torque converter assembly can be checked by turning the clutch hub with snap ring pliers can be checked by shaking the torque converter while listening for rattles cannot be checked
3. Center support housing Figure 17 8 Many modern transmissions and transaxles have a center support The support shown here is held in place with a retaining ring which must be removed before removing the rear planetary gearset and holding members as well as the output shaft Ford be removed The gearsets holding members and output shaft can usually be removed through the front of the case It may be necessary to remove the parking gear before removing the output shaft Once the mechanical components mentioned are removed any internally mounted accessories can be removed Examples of these parts include some servos accumulators clutch apply pistons usually used at rear of case and governors If these parts are not mounted inside the case for example if they mount inside the oil pan they will be removed with the other external components Note that many servos and accumulators are under strong spring pressure Always consult the service manual before removing any retaining rings or bolts It may be easier to leave the servos and accumulators installed in the case until it is time to inspect them and replace their seals If the transmission is filled with sludge and debris however these parts should be removed at this time for a thorough cleaning Automatic Transmission and Transaxle Parts Cleaning All automatic transmission or transaxle parts must be cleaned thoroughly This is very important because small dirt par
4. Servo piston selector Figure 17 46 Some bands are adjusted using a dial indicator and a special tool known as a servo piston selector After installing the tool and the dial indicator the piston is pushed downward and the indicator is read Ford Automatic Transmissions and Transaxles If the dial indicator reading is smaller than the manu facturer s specification a shorter pin must be substituted If the dial indicator reading is larger than the manufacturer s specification a longer pin must be substituted Install the governor in the case or on the output shaft as applicable and install the extension housing Then install a new seal on the extension housing Figure 17 47 Before installing the valve body perform an air pres sure test on the transmission to make sure the clutch apply pistons and servos are working properly Air pressure testing was discussed in Chapter 13 Figure 17 48 shows air pressure being used to check piston operation on one type of transmission After air pressure tests are complete install the valve body to case spacer plate the spacer plate gaskets and any check balls in the transmission case Carefully match the holes in the spacer plate and the new spacer plate gaskets to ensure proper fluid flow Install the valve body and a new oil filter Then install the transmission oil pan using a new gasket On a transaxle install the side valve body and oil pan if neces J Special driving tool
5. a valve body be sure that all pump mounted valve components are reinstalled in their original positions Sonnax Shiny edge must face in direction of arrow Pump WOES vanes A aa O O housing Pump Figure 17 36 The pump must be carefully reassembled to provide proper pressures and long service This vane pump is mounted in the side valve body of a common transaxle Ford rings can be made of metal or Teflon They should always be replaced during a rebuild After removing the old seal rings check the ring grooves Figure 17 37 They must not be worn Look for nicks or ridges on the groove walls that could prevent the new ring from seating properly allowing leaks Groove width can usually be checked with the new ring and a feeler gauge Figure 17 38 Check the bore surfaces that the seal rings ride against as well The bore surfaces must be round and smooth with no ridges or signs of wear Place the replace ment ring squarely in the bore to see that it conforms to the Chapter 17 Rebuilding Automatic Transmissions and Transaxles Check bearing or bushing contact surface for wear Inspect all gears seal rings must be in good condition Oil feed holes should be cleaned out Inspect each roller of tapered roller bearing Figure 17 37 f any of the shafts contain seal ring grooves the grooves should be closely inspected for wear Seal ring Feeler gauge Ring groove Figure 17 38 Seal rings
6. at the seals of the clutch assembly Universal tools are available that fit all types of assemblies DaimlerChrysler O ring Piston assembly oo Return spring Snap ring Figure 17 22 Exploded view of a clutch apply piston and related parts shows parts that must be removed during rebuilding Nissan With the piston out of the drum remove the piston seals Hard or cracked seals indicate that the clutch has been overheated If there is also a seal around the interior hub of the clutch drum inner piston seal remove it Figure 17 23 Then thoroughly clean the piston and piston bore Often clutch apply pistons and clutch assemblies are installed in the rear of the case Disassembly and assembly procedures for these assemblies are similar to those for other clutch packs Note If the check ball is missing do not attempt to install a replacement check ball Replace the apply piston Inspect the piston for cracks Also check that the air bleed check ball is free Obtain new piston seals Compare the new seals to the old ones to ensure that you are installing the proper seals on the piston In addition check the fit of the new seals by placing them in the piston bore They should fit snugly A bulge or buckle in an outer piston seal means the seal s diameter is too large A gap between an outer piston seal and the piston bore means the diameter is too small Before installing the new piston seals lubricate them with
7. for wear with a feeler gauge as shown here Disassembly is not required to make this check Nissan Fourth clutch snap ring Remove discs and plates SS GJE 6 Je Figure 17 14 The clutch packs should be disassembled to check for burned friction discs and other problems Most clutch packs are held together with a large snap ring as shown here General Motors Direct clutch pack Keep parts together and in sequence Sliding hub Figure 17 15 Inspect the clutch plates for wear burning scoring and other damage Also check the drum bushings hub splines and thrust washers Replace parts that show signs of wear or damage DaimlerChrysler Figure 17 16 Steel plates showing leopard spots are often found when the transmission or transaxle is disassembled Leopard spots are named for their resemblance to a leopard s coat and are a sign of severe clutch overheating The dark spots are areas where the metal has become so overheated that it has lost its strength and resistance to wear 408 plates a sign of prolonged slippage See Figure 17 17 Also check the tangs for wear or damage Figure 17 18 shows a used steel plate This plate is shiny which is normal for a used plate and could be reused if necessary If there is any doubt about the condition of the plates they should be replaced Steel plates are sometimes included in a transmission overhaul kit Friction discs are normally replaced as part of a trans
8. line will appear in the tool s window If the pin is incorrect a new pin must be obtained Other bands are adjusted using a special tool and a dial indicator The tool is installed with the servo piston Then the dial indicator is installed and set to zero Finally the piston is pushed downward to tighten the band against the drum and the dial indicator is read See Figure 17 46 ai Chain assembly Lower into case as an assembly shaft gear B Transfer shaft gear Figure 17 43 Carefully install the drive chain or gears A The drive chain and sprockets are usually lowered into the case as an assembly B The drive gears can be installed separately Be sure to install any washers and fasteners that were removed Ford DaimlerChrysler Dial indicator Slide output shaft back and forth Figure 17 44 After assembling all the drive train parts recheck endplay to ensure that you have installed the proper selective thickness thrust washer DaimlerChrysler Band apply pin N Pin length tool Torque wrench LS Pin length tool Figure 17 45 A special tool must be used to adjust the band on many modern transmissions and transaxles A The tool is installed with the existing band apply pin B The band is applied with the torque wrench If the pin is the correct length a white line will appear in the tool s window General Motors N Indicator ay s base N A lt gt Dial indicator Pa
9. made in selective thicknesses to control endplay All thrust washers should be checked with a micrometer to ensure proper endplay Use thicker or thinner washers as needed For instance if the endplay is 0 030 0 762mm too large a 0 030 thicker thrust washer should be obtained If endplay is insufficient a thinner selective thickness washer should be used Always recheck endplay to confirm that the proper washer was selected Miscellaneous Case Parts Service Many small parts are installed in the case including electrical switches and sensors electrical case connectors small screens in the pump output passages seals and check balls These parts are as important as the major transmission components They must be cleaned and care fully checked for wear and damage Electrical parts should be checked according to the manufacturer s instructions using the proper electrical test equipment Seals such as those used on the T V cable or the manual lever and shaft assembly should always be replaced Reassembly Once all automatic transmission or transaxle subassemblies have been rebuilt they can be installed in the transmission case Always refer to the manufacturer s service manual for the exact assembly procedures It will give procedures and specifications for the type of trans mission or transaxle being serviced Exploded views are very useful during the reassembly process Note Remember to soak the friction discs
10. pack operates properly when it is installed The clutch plates and friction discs should lock together when air is applied to the proper passage Subaru overheating or wear the drum should be replaced slightly worn drums can be turned down on a lathe If the surface must be turned down more than a few thousandths of an inch hundredths of a millimeter to remove scoring or wear the clutch drum or gearset member that the band rides on should be replaced A surface that is shiny must be sanded with emery cloth to remove the shine Some drums should be sanded around the surface perimeter while others should be sanded in an up and down direc tion Check the appropriate service literature to determine the direction in which the drum should be sanded A new band should always be used when the band s mating surface has been sanded Caution Soak new bands in clean ATF for about 15 minutes or until they stop bubbling Always use the correct fluid Figure 17 28 The friction material has worn away on the edge of this band The band must be replaced Figure 17 29 When servicing bands be sure to check the drum surface that the band rides on for signs of scoring over heating and wear Note that the surface of this drum has been sanded to remove the shine 412 Servo and Accumulator Service Band servos and accumulators should always be disas sembled to replace seals inspect for worn hard parts and remove accumulated sludge T
11. specifications and use the proper bushing removal and installation tools Ford If the pump body contains the pressure regulator or other valves remove them and make sure they are free in their bores If the valves are sticking they can be lightly polished to free them If the valves do not move freely after polishing replace the pump Figure 17 35 shows a typical valve and sleeve removed from the pump body If the valves in the pump have seals replace the seals before reinstalling the valves Note There are many variations in pump design and placement Three major types of pumps are used The pump may be placed immediately behind the converter and driven by converter lugs or it may be placed in the valve body and driven by a shaft Due to these variations only a general outline of pump rebuilding can be given in this chapter Always consult the proper service manual before rebuilding any pump To reassemble a vane pump begin by installing the outer slide and the bottom vane ring Then insert the vanes in the vane rotor Figure 17 36 The vanes must face in the proper direction Next install the upper vane ring to hold the vanes in position Install the pressure regulator compo nents and then install the cover Finally torque the fasteners to specifications To reassemble a gear or rotor pump install the gears in the proper order in the pump body Be sure to install the inner and outer gears so that any marks face upwa
12. too small the shift may be rough or the clutch may be lightly applied when it should be released Proper clearance helps ensure good shifts and long clutch life Clutch pack operation can often be checked with compressed air Figure 17 27 Air is directed to the fluid inlet port of the clutch applying the piston Piston action can be observed to verify that the clutch will operate when installed in the transmission Caution Never apply air pressure to the clutch piston unless the clutch plates and friction discs are installed If the plates and discs are not installed air pressure may push the piston far enough to jam it in its bore Repeat the clutch pack rebuilding sequence for every clutch pack in the transmission Band Service Check band friction linings for overall wear Look for burn marks glazing and nonuniform wear See Figure 17 28 Check to see that grooves are still visible and check for flaking If any material can be scraped off the band should be replaced Look for cracks or embedded metal particles Also check bands for cracked ends broken ears or distortion See Figure 17 29 Bands showing signs of wear or damage must be replaced The drum surface that the band rides on should also be inspected If the surface shows signs of severe scoring Air nozzle Bench test clutch Figure 17 27 Clutch pack operation should be checked with air pressure before transmission assembly This will ensure that the clutch
13. Extension housing Figure 17 47 After installing the extension housing install a new rear seal using the proper driver Worn extension bushings should also be replaced DaimlerChrysler Dial indicator used to measure piston stroke Brake piston feed hole O70009 Air gun Figure 17 48 Always perform an air pressure test on the transmission before installing the valve body Band movement or a sharp thunk from the clutch packs indicates that the air pressure is operating the holding members and that all seals and passages should channel fluid properly DaimlerChrysler Chapter 17 Rebuilding Automatic Transmissions and Transaxles 419 sary At this point you are ready to install the torque converter Prior to installation the converter can be checked for proper endplay as shown in Figure 17 49 The tool shown has an expanding pilot that can be tightened firmly into the splined hole for the turbine shaft Make sure the tool is fully seated on the hub and lock the tool in place by turning the threaded inner post Mount a dial indicator on the tool A typical procedure calls for positioning the plunger so it contacts the converter shell With the dial indicator in place zero the indicator Then pull up on the tool s handles The reading obtained is the total endplay of the turbine and stator If endplay is not within specifica tions the torque converter must be replaced A rough check of endplay can sometimes be made by in
14. Figure 17 42 A clutch and gearset assembly is shown being installed in the transmission case Make sure that parts are properly seated Nissan Caution Never install a transmission on a vehicle if the input and output shafts are binding The transmission will be badly damaged if it is operated with binding shafts Check the output shaft endplay using a dial indicator as shown in Figure 17 44 If the endplay is not within spec ifications the original selective fit thrust washer must be replaced Most units have only one selective fit thrust washer Do not try to adjust endplay by changing other washers Note Some makers specify input and out put shaft endplay specifications Check both input and output shaft endplay when specified Never attempt to compensate for exces sive endplay at one shaft by reducing endplay at the other shaft If not done already install the servos in the trans mission case Then install the band apply linkage and adjust the bands to specifications In many cases the proper band adjustment is obtained by changing the length of the band apply pin Proper pin length is usually obtained using a special tool and a torque wrench as illustrated in Figure 17 45 The special tool is installed along with the existing band apply pin Then the pin is applied against the band using the torque wrench The correct torque must be applied for the reading to be accurate If the pin is the correct length a white
15. Then install the extension housing and other output shaft parts Install the drive chain or transfer gears as necessary Install the servos and adjust the bands Also install any case mounted accumulators electrical switches and other case parts Then air pressure test the transmission Install parts that are installed inside the oil pan such as the valve body spacer plates check balls filter etc Then install the oil pan Check the converter for wear or internal damage and then install it Make sure the converter is installed properly on the transmission shafts and the pump drive hub when used is fully engaged in the front pump Review Questions Chapter 17 Please do not write in this text Place your answers on a separate sheet of paper 1 When rebuilding an automatic transmission you should work on one__ at a time so that parts are not mixed up Before disassembly clean the of the transmis sion or transaxle What can be learned from inspection of the oil pan and its contents Does the presence of a few aluminum particles in the oil pan mean that the transmission or transaxle is severely damaged Why It is usually easier to remove the front pump seal with the ___ still installed A may be installed on the back of some pumps In this case a set of and will be found directly behind the pump Many clutch packs and planetary gears are held in place by ____ During the rebuilding proce
16. This sample chapter is for review purposes only Copyright The Goodheart Willcox Co Inc All rights reserved Chapter 17 Rebuilding Automatic Transmissions and Transaxles After studying this chapter you will be able to Disassemble an automatic transmission Inspect the internal parts of an automatic transmission Reassemble an automatic transmission Disassemble an automatic transaxle Inspect the internal parts of an automatic transaxle Reassemble an automatic transaxle Check endplay of an automatic transmission or transaxle Perform air pressure checks on an automatic transmission or transaxle Technical Terms Endplay Leopard spotting Soft parts Clutch clearance V blocks Introduction Rebuilding or overhauling automatic transmissions and transaxles requires extensive knowledge and careful work habits This chapter will outline automatic transmission and transaxle overhaul procedures If you have studied the information in Chapter 3 and in Chapters 8 10 you will be familiar with the components and tools discussed in this chapter This chapter presents general procedures for rebuilding automatic transmissions and transaxles Always refer to the manufacturer s service manual for specific information It will contain accurate instructions for disas sembling cleaning inspecting and rebuilding the unit at hand Note that certain procedures performed as part of the rebuilding operation valve b
17. and grooves are vital to proper operation of the transmission or transaxle hydraulic system They should be carefully checked to ensure that they can do a good job of sealing Using a feeler gauge as shown here the maximum end clearance of a new seal ring in its groove should be about 0 003 0 006 0 07mm 0 14mm bore and that the bore is round The ring should touch the bore all the way around Parts having worn or damaged seal ring grooves or bores should be replaced Always install new seal rings carefully using plenty of transmission fluid as a lubricant Bearing and Thrust Washer Service All transmission bearings and thrust washers should be checked for wear and scoring A badly worn thrust washer is shown in Figure 17 39 This washer should be replaced General procedures for checking bushings and washers were discussed in Chapter 4 Figure 17 40A shows the procedure for checking bushing wear in a sun gear Figures 17 40B and 17 40C show the procedure used to replace a bushing Note the use of special tools to remove the old bushing and install the new one Figure 17 39 This thrust washer is badly worn and should be replaced If you encounter a thrust washer showing this degree of wear remember to inspect the part the washer rides against Chances are good that the riding surface of the part is also worn out There are many thrust washers in modern automatic transmissions and transaxles Some of these thrust washers are
18. and install the unit in a holding fixture Before beginning the disassembly procedure make sure you have the proper tools and a service manual that covers the transmission model to be rebuilt Clean the outside of the transmission transaxle thoroughly and check shaft endplay Then remove the oil pan filter and valve body On a transaxle remove the drive chain or transfer gears as necessary Inspect and save all small parts After the valve body has been taken off the front pump when used and internal parts can be removed Removal of the parts will vary according to the internal construction of the transmission or transaxle and whether or not it has a center support Carefully note the condition of all parts as they are removed from the case Then remove any other accessory parts such as servos accumulators and modulators from the case After disassembly thoroughly clean all internal parts and make further inspections for wear or damage The converter and oil cooler lines should also be cleaned Determine what replacement parts will be needed and order them Chapter 17 Rebuilding Automatic Transmissions and Transaxles 421 The clutch packs are among the most critical parts of the transmission They should be carefully inspected and serviced Disassemble the clutch packs and inspect the plates for wear The friction discs are usually replaced as part of an overhaul The steel plates are often replaced Check the bands for wear cra
19. bands and all rubber parts in fresh trans mission fluid before installation hammer Special puller jaws Overdrive carrier ATi Op 7 Pull out a worn bushing Force new bushing into overdrive carrier Figure 17 40 Check all bushings for wear and replace those that are worn A Checking a sun gear bushing B Removing a planet carrier bushing C Installing a new planet carrier bushing DaimlerChrysler General Motors Begin reassembly with the rear of the case If the case contains a low and reverse clutch that has not been serviced prior to this point disassemble and clean it Install new seals on the clutch apply piston Install the piston as well as the friction discs and steel plates Make sure the clutch clearance is correct and install the retaining snap ring If the unit uses a rear band install the band in the case but do not install the band apply linkage See Figure 17 41 Automatic Transmissions and Transaxles Install rear band Install band retaining pin Figure 17 41 The location of a band in the case on one type of transmission is shown In most instances the band should be installed before installing the drum or gearset member on which it will ride DaimlerChrysler Install the rear planetary gearsets and the output shaft Be careful to align all parts before installing any snap rings or bolts After the snap rings or bolts are in place make sure the output shaft wi
20. cking or burning Defective bands should be replaced Band servos should be disassembled cleaned and inspected After the instal lation of new seals the servos are ready to be reinstalled Accumulators are rebuilt in the same manner as servos The one way clutches should be checked to ensure that they turn in one direction only Planetary gearsets should be checked for obvious defects such as chipped teeth Also check the bushings bearings and washers at all locations in the transmission Check the transmission transaxle shafts Inspect the input and output shafts for wear bending or warpage Also check all the case parts such as screens valves and seals for wear and damage Seals should always be replaced To reassemble the transmission or transaxle start by soaking all new friction discs and bands in transmission fluid Then install the output shaft rear planetary gearsets clutches bands and other components at the rear of the case Remember to reinstall all snap rings in their original positions Then install the center support if the transmis sion is equipped with one Install the front planetary gearsets and clutches as complete assemblies as required Measure the assembled height to ensure proper assembly Install any bands or case mounted clutches Then install the oil pump Check the transmission endplay and make sure that all shafts turn Install the governor on the output shaft or in the case as applicable
21. d damage Replace any defec tive parts To reinstall the belt place it in position in the pulleys and lubricate all parts with the correct type of fluid Then slowly release the levers on the special tool Finally inspect the belt to ensure that it is properly reinstalled Oil Pump Service The front oil pump must be disassembled to check it properly Most pumps are held together by bolts Some pumps contain the pressure regulator valve and other valves A few pumps contain a clutch apply piston assembly Once the pump has been taken apart check it for wear in areas where the gears rotors or vanes ride against the stationary pump body Badly worn scored or pitted pumps can usually be detected visually Figure 17 31 Scratch the suspect area with a fingernail to confirm the presence of wear or scoring In addition the condition of the pump can be assessed with the help of feeler gauges Figure 17 32 Since the oil pump is designed to provide much more pressure than needed a slightly worn pump can be reused When reusing an old pump make sure the wear is slight and the parts are reinstalled in their original positions The pump s internal elements usually have factory marks to help ensure proper installation Always replace the front pump seal no matter how good it appears Replace the pump bushing if needed The pump bushing is critical since a worn bushing can cause the new seal to leak Proper removal and installation tools sho
22. e to disas semble the gearset and check the bearing Bushings can be checked visually If a bushing shows signs of wear or scoring replace it A bushing that looks good can be excessively worn Check bushings for wear by inserting the mating shaft or race into the bushing and trying to rock the shaft or race back and forth If the shaft or race rocks excessively the bushing is loose and should be replaced Clutch Pack Service One of the most important parts of automatic trans mission overhaul is the proper checking and rebuilding of the clutch packs These operations are discussed in the following sections Clutch Pack Disassembly and Inspection To begin disassembly use a screwdriver to remove the snap ring that holds the plates and friction discs in the clutch drum See Figure 17 14 Then remove the plates and discs Unless they are excessively worn the discs and plates will fall out when the drum is turned over Keep all the steel plates together noting if there are any reaction plates thicker steel plates at the top and bottom of the stack Figure 17 15 Never interchange one set of clutch pack parts with another Inspect the steel plates Look for discoloration which is caused by overheating and is often a sign of a badly slipping clutch pack A common sign of overheating is leopard spotting Figure 17 16 Look for worn or scored Clearance Planet gear Figure 17 13 The planet gears and planet carrier can be checked
23. ecked Add a measured amount of transmission fluid to the torque converter Nissan Install lt 2 y converter handles Slowly lower torque converter J Make sure converter is installed completely Figure 17 52 To install the torque converter turn the trans mission or transaxle until the turbine shaft faces up and lower the converter into place Make sure the converter is completely installed over the shaft splines or it will bind and be damaged when the transmission or transaxle is reinstalled in the vehicle Ford Caution Under no circumstances should you install the torque converter on the fly wheel or flexplate before installing the transaxle or transmission on the engine The splines of the transmission shafts pump and converter can be damaged Automatic Transmissions and Transaxles l Measure torque converter for Straightedge full engagement into transmission Figure 17 53 After installing the torque converter make sure it is completely seated on the input shaft and stator shaft Also make sure the lugs on the pump drive hub are fully engaged in the front pump Measuring the installed depth of the torque converter with a rule and straightedge as shown helps verify that installation is correct DaimlerChrysler Summary The major steps in transmission transaxle rebuilding are disassembly cleaning inspection and reassembly To begin rebuilding a transmission or transaxle remove the torque converter
24. ecked for wear or damage General Motors Remove the front oil pump seal as shown in Figure 17 6 It is generally easier to remove the seal before the oil pump is removed because the extra weight of the transmission transaxle assembly allows you to use the slide hammer more efficiently The front pump seal should always be changed when the pump is serviced The oil pump can be removed next Manufacturers sometimes recommend removing the input shaft before removing the oil pump However some transmissions and transaxles are constructed so that the input shaft is pressed into the front clutch drum In these designs the shaft cannot be removed before the pump The pump usually fits tightly in the case and some pressure must be applied to remove it Some pumps can be removed by prying them out with a screwdriver or pry bar once the valve body has been removed Others must be removed with slide hammers or special pullers Figure 17 7 When removing the oil pump always look for thrust washers which may fall out of place A few oil pumps have a clutch apply piston installed in their inner face When Seal remover adapter Remove old front pump hammer seal Figure 17 6 t is easier to remove the front pump seal with the transmission or transaxle assembled The weight of the unit allows the slide hammer to exert more force on the seal Ford Pullers Figure 17 7 Some pumps can be removed by pushing them out from the rear On man
25. erter onto the trans mission shafts Figure 17 52 In this case add only about 1 pint of fluid and spin the converter to distribute it to the outside of the converter internals Place the torque converter over the input shaft and push it into the converter housing The internal splines of the converter will move into contact with the splines of the stator shaft and input shaft It may be necessary to wiggle the converter while pushing on it to get it to engage with the transmission shafts The converter may also need to be rotated to line up the lugs on the pump drive hub with the slots on the front pump The lugs should fully engage the front pump To verify that the torque converter is properly installed some manufacturers recommend checking it with a measuring rule and a straightedge Figure 17 53 The reading is then compared to factory specifications Torque wrench Converter clutch torquing tool Figure 17 50 Checking the converter stator one way over running clutch with a special tool and a torque wrench If the wrench turns easily in one direction and locks up in the other direction the one way clutch is working properly Ford Pour about 2 1 8 quarts of ATF into converter housing Check for hub wear Torque converter Figure 17 51 Once the torque converter has been cleaned check it out before reinstalling it The pump drive hub can be checked for wear and the internal operation of the converter can be ch
26. gs Remove the clutch apply piston from the drum Figure 17 22 If the piston sticks in the drum it can sometimes be removed by slamming the drum downward on a block of wood or a wooden workbench This will Figure 17 19 f friction disc material can be scraped off with a fingernail the friction material is burned A disc in this condition cannot be reused and should be discarded ENE BBS WALSH se ERE a A Dr At Figure 17 20 The friction material of a friction disc will some times wear away completely leaving the steel backing exposed This disc should be replaced Water in the transmission will also cause the friction material to separate from the steel backing Chapter 17 Rebuilding Automatic Transmissions and Transaxles 409 often jar the piston loose Compressed air can also be used to blow the piston from the drum Place the drum down ward on the workbench and insert an air nozzle in the oil feed hole in the center of the drum A short burst of air should push out the piston remove a piston point the open end of the drum away from yourself and others Direct the piston into a pile of rags or another soft surface so that it does not fly out and become damaged or cause injury Also use a regulated amount of air pressure Warning When using compressed air to Compressor tool Remove Return piston springs snap ring Figure 17 21 A special compressor must be used to remove the clutch apply piston in order to get
27. he inspection and repair of servos and accumulators was covered in Chapter 15 Overrunning Clutch Service All overrunning clutches in the transmission or transaxle should be checked to ensure that they turn freely in the direction they should and lock up in the other direc tion See Figure 17 30 Any overrunning clutch that turns in both directions must be replaced Also any clutch showing signs of wear should be replaced Make sure the new clutch turns in the proper direction when installed CVT Belt and Pulley Service CVT belt and pulley arrangements are similar but each one has specific repair processes Always consult the proper service information before beginning disassembly Belt removal on most CVTs requires a special tool that is a combination of a holding fixture and a clamping tool The CVT assembly is placed in the holding fixture A U shaped clamping ring is positioned around the sliding portion of the drive pulley and locked to levers on the tool When the levers are depressed force is applied to the clamping ring Figure 17 30 Testing a one way clutch A Clutch turns easily in one direction B Clutch does not turn at all in opposite direction Automatic Transmissions and Transaxles driving the bottom portion of the pulley downward to the fully open position With both pulleys in the fully open position the belt can be easily removed Once the belt has been removed check the belt and pulley sheaves for wear an
28. he sun gear inside the input shell This snap ring must be removed before the clutch pack and other internal parts can be removed In addition some rear planetary gearsets are held in place by a snap ring on the front of the output shaft This snap ring must be removed in order to completely disassemble these components Make sure the shaft does not fall out of the case after the snap ring is removed Also do not distort or stretch snap rings when removing them Use snap ring pliers or another suitable tool As mentioned some automatic transmissions have a center support The center support in an automatic trans mission may be retained by one or two case bolts located under the valve body and sometimes by bolts on the outside of the case Other center supports are held in place by a retaining ring in the case Figure 17 8 The center support keeps the rear clutches and gearsets in place Always make sure the center support bolts or retaining rings have been removed before attempting to remove the center support and mechanical components Caution Attempting to drive the rear clutch planetary gearset and shaft assem blies from the case without first removing the center support fasteners will severely damage these components the center support and the case Once the center support has been removed the rear planetary gearsets bands clutches and output shaft can Chapter 17 Rebuilding Automatic Transmissions and Transaxles 405
29. her moving parts are badly worn If this is the first time the oil pan has been removed for service it is normal to see a few aluminum particles in the pan These particles were left over from case machining opera tions at the factory Removing the oil pan gives you access to the filter and valve body The filter may be pressed into a case passageway and held in place with a clip on the valve body or it may be bolted directly to the valve body Remove the filter at this time After the filter has been removed the valve body bolts can be unfastened and the valve body can be removed from the case As you lift the valve body from the case carefully note the position of all valve body parts including springs oil feed tubes linkage attachments and check balls If applicable you should also remove the vacuum modulator push rod and throttle valve from the case at this time See Figure 17 3 Place the assembled valve body and related parts as well as any modulator parts together on the workbench If you are disassembling a transaxle remove any side or top covers then remove the side or top valve body Note the location of all tubes and check balls If the transaxle uses a transfer plate remove it also Remove the bolts holding the extension housing to the case Extension housings are sometimes called tailshaft housings The extension housing should pull off over the output shaft after the bolts are removed A few extension housings con
30. ke sure it is snug in its groove See Figure 17 25 Press lightly on piston as you work the lip seal downward Seals direct clutch piston Housing and drum assembly direct clutch Figure 17 24 This special tool can be fabricated from copper tubing and wire to make lip seal installation easier This tool will be much less likely than a feeler gauge to cut the new seal General Motors g A Retaining AJ 4 x mP SS Figure 17 25 To reassemble the apply piston and return spring assembly depress the return springs below the snap ring groove and install the snap ring Sometimes it is easier to install the snap ring by hand or with a small screwdriver than it is to install it using the snap ring pliers Ford Automatic Transmissions and Transaxles If the clutch pack uses a reaction plate next to the apply piston install it now Then install the friction discs and steel plates alternating them and using new parts as required Always use new friction discs Some technicians reuse the steel plates after buffing the plates to remove the shiny surface Some friction disc manufacturers recom mend that if reused the old steel plates be installed without buffing These manufacturers state that buffing the steel plates causes rapid wear of the new friction discs It is often quicker and therefore cheaper to install new steel plates If the clutch pack uses a reaction plate at the top install it before installing the ou
31. lanetary gears for wear nicks and chipping Figure 17 11 shows a gearset that has been destroyed Figure 17 12 shows a sun gear being inspected for tooth damage Slightly nicked gears can cause noises and vibration and eventually they will fail completely Splines found on the gearset members should also be checked for wear and damage Check the clearance between the planet gears and the planet carrier to deter Damaged planet gears eaa Ao Planet carrier Figure 17 11 Worn or damaged planet gears can result in a noisy transmission or transaxle Severely damaged gears will strip off or jam resulting in a no drive condition BBU Inc Inspect all gear teeth closely Figure 17 12 Gear teeth on all of the planetary gears should be closely inspected for chips cracks scoring and wear Also check for worn snap ring grooves or bushings Replace any damaged gears DaimlerChrysler Chapter 17 Rebuilding Automatic Transmissions and Transaxles mine the amount of endplay Figure 17 13 Planetary gearsets often contain bushings or needle bearings that wear out These should be carefully checked as well Any parts that are worn or damaged should be replaced Visually inspect needle bearings and Torrington flat bearings and try to rotate them by hand If you feel any roughness when turning a clean bearing or a gear that rides on a bearing replace the bearing If you suspect that a bearing inside a gearset is worn take the tim
32. ll turn Also make sure that all the thrust washers are installed correctly If a center support is used install it now Install the center support snap ring and or bolts and make sure the output shaft will still turn In many designs the clutches must be assembled before they are installed in the case The height of the assembly may be checked to ensure that it meets specifi cations With some transmissions and transaxles the clutches and front gearsets will be assembled prior to installation Install any such assembly at this point See Figure 17 42 Also if the unit has a front band install it now If the transmission or transaxle has a set of clutch plates and friction discs directly behind the front pump install it Note This step does not apply to transaxles with a valve body mounted pump now making sure to alternate discs and plates Next place the proper gasket on the case and install the front pump As you slowly tighten the pump fasteners check that the input and output shafts can be turned by hand If either shaft begins to bind find the cause and correct it before proceeding If a transaxle is being worked on install the chain and sprockets now Also install the transaxle transfer gears if applicable See Figure 17 43 Chapter 17 Rebuilding Automatic Transmissions and Transaxles Wash and blow off case carefully Blow out all passages Install shaft in case gearset and clutch assembly
33. mission overhaul and are usually included in a transmis sion overhaul kit Worn or damaged discs may be charred glazed or heavily pitted The friction lining may scrape off easily with your fingernail See Figure 17 19 In some instances all the friction material will be missing from the friction discs Figure 17 20 shows a friction disc that has lost almost all its friction material Check the condition of the channels on the inside surface of the clutch drum and the splines on the clutch hub Severe disc damage may cause the hub splines to be stripped Worn or damaged parts should be replaced Figure 17 17 This plate was scored by the scraping action of foreign material between the plate and the friction disc The foreign material may be from another part of the transmission or transaxle or it may be the result of severe damage to the friction discs Figure 17 18 A normally worn steel plate will be shiny as shown here This steel plate could be reused if necessary Before deciding that the plate is good however check it for warping and damage to the teeth Automatic Transmissions and Transaxles Removing the Apply Piston Rebuilding a clutch pack requires the use of a special spring compressor Figure 17 21 Install the spring compressor and compress the return spring Remove the retaining snap ring with snap ring pliers or a screwdriver Release the spring compressor then remove the spring retainer and the return spring or sprin
34. ody service for example were covered in Chapter 15 Note For transaxle final drive rebuilding information refer to Chapter 18 Although a typical automatic transmission or transaxle contains many parts it can be successfully rebuilt if you follow logical procedures Special service tools are sometimes needed when rebuilding an automatic transmission or transaxle These tools can be purchased from the vehicle dealer or ordered directly from the manufacturer Refer to Chapter 2 for more information on special service tools used to service auto matic transmissions and transaxles Automatic Transmission and Transaxle Disassembly Before beginning disassembly of a transmission or transaxle clean the outside of the unit thoroughly and mount the unit in a holding fixture Figure 17 1 If a holding fixture is not available place the assembly on a clean workbench The workbench should be constructed so that transmission fluid can drain into a catch basin As you remove the major parts of the transmission or transaxle set them aside for further disassembly Then work on one subassembly pump clutch pack or servo for example at a time This will help you keep things straight Removing External Components The first step in disassembly is to remove the torque converter holding tool and the torque converter from the transmission or transaxle Before proceeding check the converter housing for dents or obvious leakage and for s
35. rd Then place the pump cover over the pump body and install and tighten the bolts in the order specified by the manufacturer Always use a torque wrench to tighten the bolts If the pump incorporates a clutch apply piston replace the seals as explained in the clutch pack rebuilding section and then reassemble the pump as explained above The Code 62 Pump Package Part KO62 Figure 17 34 The kit shown here is used to repair a chronic bushing failure problem on a common truck transmission It also corrects torque converter slippage and resultant computer con trol system problems The replacement bushing is an improved type that resists wear Instructions furnished with the kit explain how to drill and enlarge lube holes to further increase bushing life and how to install an improved converter drainback valve Superior Note Some pumps installed in the case require that a special tool called an aligning band be placed around the two halves of the pump to ensure that they are properly aligned before the bolts are tightened Seal Ring Service Seal rings are critical to proper transmission and transaxle operation since they seal in hydraulic fluid going from the valve body to the bands and clutch packs Seal Automatic Transmissions and Transaxles Figure 17 35 Exploded view of an oil pump mounted valve and its aluminum sleeve The valve and sleeve should be care fully checked for sticking scoring or other damage As with
36. s right away eliminating time lost waiting for parts Note During inspection it is not absolutely necessary to check the soft parts such as F gaskets lip seals O rings seal rings and friction discs These parts are replaced during a rebuild Checking the soft parts however will often help you to determine what caused the transmission or transaxle to fail Shaft Service Automatic transmission and transaxle shafts including input output and stator shafts require little service Check seal ring grooves and bushing surfaces for wear scoring and overheating Inspect shaft splines for wear or damage Figure 17 9 Any shaft with worn or damaged splines should be replaced If you suspect that a shaft is bent or warped it can be checked with V blocks and a dial indicator as shown in Figure 17 10 Check for snap ring groove wear Inspect for worn splines Cheek ion dean in oil feed DSS Inspect oil seal ring groove Check for worn bushing riding surface Figure 17 9 After the transmission or transaxle has been disassembled check shaft splines bearing journals and ring grooves for wear Dial indicator V blocks Rotate transmission shaft Figure 17 10 nput and output shafts can be checked for bends or warpage using V blocks and a dial indicator Never attempt to straighten a bent or warped shaft Toyota Automatic Transmissions and Transaxles Planetary Gearset Service Check the teeth of the p
37. serting a pair of snap ring pliers into the splined turbine hub and pulling upward Observing the plier movement will indicate how much endplay there is The one way clutch can also be checked at this time Place snap ring pliers down through the pump drive hub and expand them into the internal splines on the one way clutch These splines mate with external splines on the Threaded gt Endplay checking inner post a tool installed into converter Sleeve ae KA D T D A AN a AiE OTR LLL I X indicator Figure 17 49 Converter endplay can be checked with the special tool shown here A The endplay checking tool must be fully seated on the converter hub and locked in place B After mounting the dial indicator on the tool zero the indicator and pull up on the tool s handles The reading obtained is the total endplay of the turbine and stator Ford stator shaft Applying torque to the pliers should turn the stator easily in one direction clutch unlocked and not so easily in the other direction clutch locked and turning the stator A special tool that engages the one way clutch inner race can also be used to check clutch operation See Figure 17 50 If the torque converter passes these tests check the converter for wear at the hub If there are no signs of wear add at least 1 quart of fresh transmission fluid to the converter See Figure 17 51 Note Some manufacturers recommend lowering the conv
38. ss gaskets seals and fric tion discs should be replaced A in all cases B C only if removed D Leopard spotting is a sign of excessive ____ only if obviously damaged None of the above What visual signs indicate that a clutch pack has been slipping Some technicians _____ steel plates before rein stalling them This removes the surface However it is often cheaper to install __ plates If clutch clearance is too _ not apply tightly and may slip the clutch pack may To remove a CVT belt use a special tool to move the drive pulley to the completely ___ position Badly scored pumps can often be spotted bya inspection Pump wear can sometimes be determined by the useof___ gauges A slightly worn pump can be 15 Fasteners such as or center support to the case are used to hold the 16 Check the torque converter endplay with a __ indicator Match the transmission component with the measuring device used to check it Dial indicator and V blocks Micrometer 17 Clutch pack clearance ___ 18 Band servo operation ___ 19 Shaft straightness ___ 20 Shaft bushings __ _ Air pressure Vacuum pump and gauge Feeler gauge Visual inspection 21 Overheated steel plates _ 22 Thrust washer thickness _ Inserting and rocking the shaft ASE Type Questions Chapter 17 ot indicate is right A A only B B only C Both A and B D Neither A nor B
39. tain an output shaft bearing which supports the output shaft In this design the bearing snap ring must Vacuum modulator Figure 17 3 The vacuum modulator and throttle valve can be removed now to prevent damage Do not lose the pushrod if the modulator uses one Ford be expanded before the extension housing can be slid from the shaft After removing the extension housing you can remove the governor This step applies only to governors mounted on the output shaft not those mounted in the case If you are disassembling a transaxle with a drive chain check the chain for wear as shown in Figure 17 4 Then remove the chain and sprocket assembly If the transaxle uses transfer gears remove the gears and care fully check the teeth for wear See Figure 17 5 Wiggle up and down f f If dimension exceeds specs about 1 1 16 inch replace drive link Figure 17 4 Always check the drive chain for wear before disassembly To disassemble remove any snap rings that may be holding the sprockets to their shafts Position the chain tensioner away from the chain Then remove the chain and sprockets as an assembly by carefully sliding both sprockets off the transaxle shafts Save any thrust washers placed between the cover and the sprockets DaimlerChrysler S Output X shaft gear o OX Transfer shaft gear FJ Nee SS Rear cover Figure 17 5 Drive gears are installed behind a sheet metal cover They should be ch
40. ter snap ring Caution A dry friction disc will burn severely the first time the clutch is applied To prevent this soak new friction discs in clean transmission fluid before installing them Allow them to soak for about 15 minutes or until they stop bubbling Always use the correct type of automatic transmission fluid The vehicle owner s manual should list the proper ATF The fluid type may also be stamped on the transmission dipstick With the clutch pack now assembled measure the clutch clearance or the distance between the pressure plate and outer snap ring Clutch clearance is checked with a feeler gauge Figure 17 26 The exact placement of the feeler gauge will vary between makes Most Figure 17 26 One of the most critical parts of transmission rebuilding is checking the clutch pack clearance Incorrect clearances must be fixed by replacing the pressure plate or snap ring with one of the proper thickness Chapter 17 Rebuilding Automatic Transmissions and Transaxles 411 manufacturers have clearance adjustment kits consisting of snap rings or pressure plates of varying thicknesses Replacing a snap ring or pressure plate with one of a different thickness will change the clearance Clutch clearance is an indicator of how tightly the plates and discs are packed This is important because it affects transmission operation If the clearance is too large the clutch will not be applied tightly and may slip If the clearance is
41. the torque converter will be full of dirt and varnish A torque converter that is filled with dirt or metal particles can be cleaned with a converter flusher Converter flushers were introduced in Chapter 3 A heavily varnished converter however is difficult to clean and is often replaced If there is evidence of fluid contamination the oil cooler and cooler lines must be flushed out One way to do this is to use an oil cooler and line flusher and follow up with a blast of compressed air directed into one of the cooling lines Have a drain pan available to catch solvent flowing from the other line Do not apply full air pressure to the cooling lines as this could rupture the oil cooler A badly contaminated oil cooler cannot be completely cleaned Therefore the radiator should be replaced or the cooler should be bypassed by installing an external oil cooler when a badly contaminated unit is encountered Parts Inspection and Repair Once the transmission or transaxle is disassembled and cleaned the parts can be inspected replacement parts can be ordered and subassemblies can be rebuilt In this section parts inspection and repair will be covered when describing the service of each subassembly During an actual rebuild internal parts will be inspected during and immediately after the unit is taken apart and cleaned You should inspect transmission or transaxle parts one subassembly at a time In this way you can order replace ment part
42. ticles or varnish formation can cause a passageway to plug up a valve to stick or a seal to leak Carefully scrape all old gasket material from the case oil pan and other parts Pay attention to the gaskets on hydraulic control assemblies such as the front pump the valve body and the spacer plates Clean all metal parts including the case with a safe solvent It may be necessary to soak parts overnight Do not clean clutch friction linings or seals with solvent To avoid having a confusing pile of parts always remember to work on one subassembly at a time while cleaning other flammable solvents A fire could Warning Never clean parts with gasoline or result Dry the cleaned parts with compressed air if possible or allow them to air dry Do not use rags or shop towels to dry the parts because they will leave lint on the parts The lint left behind can cause valves to stick It is better to leave slight deposits of solvent on the parts than to dry them with rags or shop towels Once cleaned cover the disassembled parts with a clean lint free cloth if they are to sit out overnight Drain the torque converter If there is a drain plug remove it and set the converter upright with the drain at the lowest point On converters without a drain plug lay the center opening face down This will allow most of the old transmission fluid to drain from the converter If the internal parts were very dirty or heavily coated with varnish
43. transmission fluid Petroleum jelly can also be used but other types of oil or grease will damage the seals Carefully install the new piston seals on the clutch drum hub and clutch piston as applicable The new seals should fit snugly but not too snugly Lip seals must be installed on a piston so the sealing lip will be directed toward the hydraulic pressure toward the back of the drum Install the clutch piston in its bore The type of piston seal determines the installation method If O ring seals are Figure 17 23 Inner piston seals can usually be removed with a small pick Inspect the seals carefully for damage and excessive wear 410 used the piston can be pressed or tapped into the bore after being thoroughly lubricated A piston using a lip seal must be worked into place with a feeler gauge or a special seal installation tool A satisfactory tool can be made from a stiff piece of wire and a small length of copper tubing Use the tool to push in the seal as you press on the piston See Figure 17 24 Once the piston is in place check its installation by trying to turn it If you cannot turn the piston the seal is not properly positioned Once you are sure the piston is properly installed put the piston return spring s and spring retainer back in posi tion on the piston Then use the spring compressor tool to move the return spring s and retainer past the groove for the retaining snap ring Install the snap ring and ma
44. tripped converter attaching bolt holes Check the converter crankshaft pilot projection for burrs or damage and check Automatic Transmissions and Transaxles the oil pump driving lugs if used for wear or burrs Then check input and output shaft endplay as shown in Figure 17 2 Endplay back and forth movement of the shaft should be checked before the transmission or transaxle is disassembled and again after it is reassembled Record the endplay readings for later reference Excessive endplay indicates wear of the thrust washers and other parts This should be corrected during the rebuilding process Automatic Transmission stand or fixture Figure 17 1 t is much easier to overhaul a transmission or transaxle if it is placed in a special holding fixture Nissan Dial indicator Dial indicator Figure 17 2 Always check endplay before disassembling the transmission The service manual will contain the endplay spec ifications and the procedures for setting up the dial indicators A Checking input shaft endplay B Checking output shaft endplay General Motors Chapter 17 Rebuilding Automatic Transmissions and Transaxles 403 After checking endplay remove the oil pan Check the pan for metal particles varnish buildup and sludge Excessive sludge indicates that the holding members are burnt and the fluid has been overheated Metal particles usually indicate that the torque converter oil pump plan etary gearsets or ot
45. uld always be used Figure 17 33 Stake the bushing in place to prevent it from moving Some transmissions and transaxles have high pump bushing failure rates Aftermarket kits have been developed to solve this problem Figure 17 34 Scored area Figure 17 31 This pump body is severely scored at the pump gear riding surface A pump body in this condition should not be reused When the pump body shows this much wear check the pump cover for similar wear Chapter 17 Rebuilding Automatic Transmissions and Transaxles Measure rotor end clearance A Measure rotor tip A Typical tip clearance 0 005 to 0 010 in Measure rotor side clearance C Typical side clearance 0 004 to 0 008 in Figure 17 32 These three checks will determine whether the pump can be reused These checks apply to gear and rotor pumps Always refer to the service manual for wear speci fications A Checking the clearance between rotor or gear faces and a straightedge laid across pump body end clear ance B Checking the clearance between the tips of the inner and outer rotor lobes or gear teeth tip clearance C Checking the clearance between the outer rotor or gear and the pump body side clearance DaimlerChrysler Hydaulic gt L__ press ram pen Bushing driver Old bushing Figure 17 33 Worn pump bushings can be replaced with new bushings The old bushing is pressed out as shown here Always check the service manual for exact
46. y transmissions and transaxles how ever the pump cannot be reached from the rear and must be removed with a slide hammer or special puller Ford Automatic Transmissions and Transaxles this is the case a set of friction discs and clutch plates is installed directly behind the pump These parts should be removed and placed with the pump for later service Removing Internal Components With all the external parts out of the way the internal components such as the input shaft bands clutch packs planetary gearsets and output shaft can be removed Removal steps are similar for all manufacturers The major factor affecting disassembly is whether or not the transmis sion or transaxle uses a center support On units without center supports removing internal components is usually a simple matter once the oil front pump is removed A typical procedure might involve loos ening the front band adjuster sliding the band out of the case and then removing the forward clutch packs front planetary gearset and input shell as an assembly Be sure to save all thrust washers as they come out with these parts Once the front components have been removed the rear planetary gearsets and holding members as well as the output shaft can be removed Rear gearsets are removed through the front of the case The output shaft will usually come out through the rear of the case Note that some clutch packs are held in place by a snap ring located on t
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