GM Prizm/Nova 1985-1993 Repair Guide

Overhaul

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See Figures 1 through 8


WARNING
The use of the correct special tools or their equivalent is REQUIRED for this procedure.

Before servicing the transaxle, it is important to insure cleanliness. The outside of the case should be thoroughly cleaned with solvent or spray cleaner. Any dirt entering the unit may damage moving parts. The work area and workbench should be cleaned before the work is begun and maintained in clean condition during the repair. If the repair must be abandoned for more than a few minutes, cover the work area and components with a large cloth or sheet.

All disassembled parts should be cleaned with solvent and dried with compressed air if possible. Do not use solvent on Neoprene seals. Lubricate the seals with clean transaxle oil and use petroleum jelly to hold throughst washers in place during assembly. This eases installation and does not leave harmful residue in the system.

Before installing bolts into aluminum parts, dip the threads in clean oil or coat them with an anti-seize compound to prevent galling or seizing. Always use a torque wrench to avoid overtightening fittings. Aluminum parts are very susceptible to damage and must be handled carefully. Certain internal parts are made of very soft metals and must be protected from impacts which could cause damage or cracks. While a certain amount of force is needed to separate or assemble parts, the force should be applied smoothly and evenly; sharp impact will damage components. Reusing snaprings and circlips is not recommended; they lose their tension during the removal process.

TRANSAXLE DISASSEMBLY



  1. Remove the transaxle from the car, following procedures outlined previously. Secure the transaxle to a work stand.
  2.  
  3. Remove the clutch release fork, the clutch release bearing and the speedometer driven gear.
  4.  
  5. Remove the clutch release cylinder-to-transaxle bolts and the release cylinder.
  6.  



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Fig. Fig. 1: Transaxle assembly removed from vehicle

  1. Using the back-up light switch socket or equivalent, remove the back-up light switch.
  2.  
  3. Remove the transaxle case cover bolts and the cover.
  4.  
  5. Using a dial indicator, measure the 5th gear throughst clearance. The clearance must be 0.10-0.66mm; if not, the selective snapring will need to be replaced during reassembly.
  6.  



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Fig. Fig. 2: Measuring 5th gear throughst clearance with a dial indicator. Use the chart to select a replacement snapring if needed



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Fig. Fig. 3: Removing 5th gear; GM tool shown



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Fig. Fig. 4: Removing the set bolt



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Fig. Fig. 5: The two screwdriver trick for removing snaprings. Note the blades positioned vertically

  1. Remove the shift selector bellcrank, the set bolt, the shift and selecting lever.
  2.  
  3. Engage the gears, remove the 5th gear locknut and disengage the gears.
  4.  
  5. Remove the bolt with the lockwasher from the No. 3 shift fork.
  6.  
  7. Using a pair of small prybars or screwdrivers and a hammer, tap the 5th gear snapring from the shaft.
  8.  
  9. Remove the 5th gear hub sleeve and driven gear. Using a gear puller or equivalent, press the 5th drive gear from the shaft.
  10.  



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Fig. Fig. 6: Removing the plugs and lockbolt assemblies



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Fig. Fig. 7: Removing the reverse shaft arm bracket and idler

  1. Remove the rear bearing retainer and both bearing snaprings. Remove the reverse idler gear shaft bolt and the No. 2 shift fork shaft snapring.
  2.  
  3. Using a No. 40 Torx® bit or equivalent, remove the 3 plug, seal, spring, ball and lockball assemblies. If necessary, use a magnet to remove the seats, springs and balls.
  4.  
  5. Remove the transaxle case-to-bellhousing case bolts and tap the cases apart with a plastic hammer.
  6.  
  7. Remove the reverse shift arm bracket. Remove the reverse idler gear, throughst washer and shaft. Using a pair of prybars and a hammer, tap out the shift shaft snaprings and remove the set bolts.
  8.  



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Fig. Fig. 8: Removing the shift forks and shafts

  1. To remove the shift forks and shift fork shafts, perform the following procedures:
    1. Remove the No. 2 fork shaft and shift head.
    2.  
    3. Using a magnet, remove both balls.
    4.  
    5. Remove the No. 3 fork shaft and the reverse shift fork.
    6.  
    7. Pull out the No. 1 fork shaft.
    8.  
    9. Remove the No. 1 and No. 2 shift forks.
    10.  

  2.  
  3. Remove both the input and output shafts at the same time.
  4.  
  5. Remove the differential assembly, the magnet and the oil receiver.
  6.  

Input shaft

See Figures 9 through 15

  1. Using a feeler gauge, measure the 3rd and 4th throughst clearance. Standard clearances are: 3rd gear, 0.10-0.35mm and 4th gear, 0.10-0.55mm. Maximum allowable clearances: 3rd gear, 0.40mm and 4th gear, 0.60mm.If the 3rd gear clearance is exceeded, 3rd and 4th gears must be replaced. If the 4th gear clearance is exceeded, 4th and 5th gears must be replaced.
  2.  



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Fig. Fig. 9: Measuring 3rd and 4th gear throughst clearances



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Fig. Fig. 10: Use a split-plate and a press to remove 4th gear, bearing and synchronizer

  1. Using a small pair of prybars and a hammer, tap the snaprings from the input shaft.
  2.  
  3. Using a press and a split plate tool, press the radial ball bearing and 4th gear from the input shaft. Remove the needle roller bearings and the synchronizer ring.
  4.  
  5. Using a pair of snapring pliers, remove the snapring from the input shaft. Use a press and a split plate tool to press the No. 2 sleeve, 3rd gear, the synchronizer ring and the needle roller bearing from the input shaft.
  6.  
  7. Clean all components thoroughly and dry with compressed air if possible. Inspect components as follows:
    1. Check the input shaft bearing surfaces for scoring and/or wear; if necessary, replace the shaft.
    2.  
    3. Check the input shaft splines for wear; if necessary, replace the shaft.
    4.  
    5. Inspect the bearings for scoring, wear and/or damage; if necessary, replace them.
    6.  
    7. Check the gears and synchronizer parts for damage and/or excessively worn teeth; if necessary, replace them.
    8.  
    9. Using a dial indicator, check the shaft runout; if runout exceeds 0.50mm, replace the shaft.
    10.  
    11. Using a feeler gauge, measure the clearance between the shift forks and the hub sleeves. If the clearance is less than 0.60mm, replace the synchronizer.
    12.  

  8.  
  9. Using multi-purpose grease, lubricate the needle roller bearings.
  10.  
  11. Place the synchronizer ring onto the 3rd gear, align the ring slots with the shifting keys. Using a shop press and a split plate tool, press the 3rd gear/No. 2 hub sleeve onto the input shaft.
  12.  



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Fig. Fig. 11: Use V-blocks and a dial indicator to measure runout



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Fig. Fig. 12: Measuring shift fork clearance to hub sleeve



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Fig. Fig. 13: 3rd gear bearing, synchronizer ring and No. 2 hub



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Fig. Fig. 14: Use the chart to select the correct snapring for 3rd gear and 4th gear retention

  1. Select a snapring which will allow minimum axial play and install it onto the input shaft.
  2.  
  3. Using a feeler gauge, measure the 3rd gear throughst clearance; it should be 0.10-0.35mm.
  4.  
  5. Using multi-purpose grease, lubricate the needle roller bearings.
  6.  
  7. Place the synchronizer ring onto the 4th gear and align the ring slots with the shifting keys.
  8.  
  9. Using a shop press, press the radial ball bearing onto the input shaft.
  10.  
  11. Select a snapring which will allow minimum axial play and install it onto the shaft.
  12.  
  13. Using a feeler gauge, measure the 4th gear throughst clearance; it should be 0.10-0.55mm.
  14.  



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Fig. Fig. 15: Input and output shaft components

Output Shaft

See Figures 16 through 20

  1. Using a feeler gauge, measure the 1st and 2nd gear throughst clearance on the output shaft. Standard clearances are: 1st gear, 0.10-40mm and 2nd gear, 0.10-0.45mm. Maximum allowable clearances are: 1st gear, 0.45mm and 2nd gear, 0.50mm. If 1st gear clearance is incorrect, 1st and 2nd gears must be replaced. If 2nd gear clearance is incorrect, replace 2nd and 3rd gears.
  2.  
  3. Using a press and a split plate tool, press the radial ball bearing, the 4th driven gear and spacer from the output shaft.
  4.  



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Fig. Fig. 16: Measuring 1st and 2nd gear throughst clearances



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Fig. Fig. 17: Slotted spring pin

  1. Using a shop press and a split plate tool, press the 3rd driven gear, 2nd gear, the needle roller bearing, the spacer and the synchronizer ring from the output shaft. Remove the needle roller bearings and the synchronizer ring.
  2.  
  3. Remove the snapring.
  4.  
  5. Now press the No. 1 hub sleeve, the 1st gear/synchronizer ring, the needle roller bearing, the throughst washer and locking ball from the output shaft. Remove the needle roller bearings and the synchronizer ring.
  6.  
  7. Clean all components thoroughly and dry with compressed air if possible. Inspect components as follows:
    1. Check the input shaft bearing surfaces for scoring and/or wear; if necessary, replace the shaft.
    2.  
    3. Check the input shaft splines for wear; if necessary, replace the shaft.
    4.  
    5. Inspect the bearings for scoring, wear and/or damage; if necessary, replace them.
    6.  
    7. Check the gears and synchronizer parts for damage and/or excessively worn teeth; if necessary, replace them.
    8.  
    9. Using a dial indicator, check the shaft runout; if runout exceeds 0.50mm, replace the shaft.
    10.  
    11. Using a feeler gauge, measure the clearance between the shift forks and the hub sleeves.
    12.  

  8.  
  9. Install the locking ball into the output shaft. Install the throughst washer onto the shaft by positioning it's groove securely over the locking ball.
  10.  



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Fig. Fig. 18: Hub sleeve assembly; arrow points to engine side



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Fig. Fig. 19: Chart for selecting 1st gear snaprings



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Fig. Fig. 20: Second gear and 3rd driven gear assembled on shaft

If the output shaft was replaced, drive a slotted spring pin into the output shaft to a depth of 6.0mm.

  1. Using multi-purpose grease, lubricate the needle roller bearing.
  2.  
  3. Place the synchronizer ring onto the 1st gear and align the ring slots with the shifting keys.
  4.  
  5. Press the 1st gear/No. 1 hub sleeve assembly onto the output shaft.
  6.  
  7. Select a snapring which will allow minimum axial play and install it onto the shaft.
  8.  
  9. Using a feeler gauge, measure the 1st gear throughst clearance; is should be 0.10-0.40mm.
  10.  
  11. Install the spacer. Position the synchronizer ring onto the gear and align the ring slots with the shifting keys.
  12.  
  13. Using multi-purpose grease, lubricate the needle roller bearings and install the 2nd gear.
  14.  
  15. Using a shop press and a split plate tool, press the 3rd driven gear onto the output shaft.
  16.  
  17. Using a feeler gauge, measure the 2nd gear throughst clearance; is should be 0.10-0.45mm.
  18.  
  19. Install the spacer. Use a press and a split plate to press the 4th driven gear and bearing onto the output shaft.
  20.  

Synchronizers

See Figure 21

The transaxle is equipped with 3 synchronizers: 1st-2nd, 3rd-4th and 5th speeds.

  1. From each synchronizer, remove both key springs.
  2.  
  3. Noting the relative positions, separate the hub, sleeve and keys; be sure to scribe the hub-to-sleeve location.
  4.  
  5. Clean, inspect and/or replace any worn or damaged parts.
  6.  



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Fig. Fig. 21: Checking synchronizer function and clearance

  1. Using a feeler gauge, measure the synchronizer ring back-to-gear spline end clearance; it should be a minimum of 0.6mm.
  2.  
  3. Align the scribe marks and assemble the hub to the sleeve; the extruded hub lip should be directed away from the sleeve's shift fork groove.
  4.  
  5. Install a retaining ring. Carefully pry the ring back and insert the keys (1 at a time); be sure to position the ring so it is locked in place by the keys.
  6.  
  7. Install the other retaining ring; be sure the ring's open segment is out of phase with the open segment of the other ring. The open areas should NOT align.
  8.  

FRONT CASE



See Figures 22, 23 and 24

  1. Use an input shaft bearing removal tool (or equivalent) and a slide hammer/puller to press the input shaft's front bearing from the case.
  2.  



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Fig. Fig. 22: Removal (left) and installation of input shaft front bearing. GM tools shown

  1. Remove the bolt and bearing lockplate. Using an output shaft bearing removal tool or equivalent, and a slide hammer/puller, press the output shaft's front bearing from the case.
  2.  
  3. Using a small prybar, pry the input shaft front oil seal and the right hand differential oil seal from the case.
  4.  
  5. Using the differential side bearing cup removal tool or equivalent, and a hammer, drive the right hand differential outer race from the case.
  6.  
  7. Check and clean the case.
  8.  
  9. Using a scraper or gasket cleaning tool, remove the sealant from the mating surfaces; be careful not to gouge or damage the aluminum surfaces.
  10.  
  11. Use the input shaft seal installation tool, drive the new oil seal into the case until it seats.
  12.  



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Fig. Fig. 23: Removing and installing seals



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Fig. Fig. 24: Removing and installing case bearings. GM tool shown

  1. Drive the input shaft bearing into the case with the correct size bearing driver.
  2.  
  3. Drive the output shaft bearing into the case.
  4.  
  5. Install the right hand differential outer race into the case.
  6.  
  7. Lubricate the new oil seal with multi-purpose grease. Using the differential seal driver and a hammer, drive the new differential oil seal into the case.
  8.  

DIFFERENTIAL



See Figures 25 through 31



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Fig. Fig. 25: Removing the side bearing using GM tools

  1. Using the differential side bearing puller tool (GM J-22888-20) or equivalent, and a differential side bearing puller pilot (GM J-35378) or equivalent, press the side bearings from the differential case.
  2.  



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Fig. Fig. 26: Measuring pinion gear backlash; use the chart to select replacement throughst washers

  1. Loosen the staked part of the lockplate. Using a scribing tool, make alignment marks at the ring gear-to-case location.
  2.  
  3. Remove the ring gear-to-case bolts and tap the ring gear from the case.
  4.  
  5. Using a dial micrometer, hold a pinion and side gear toward the case and measure the backlash of the other side gear; it should be 0.05-0.20mm. If the backlash is not within specifications, replace the throughst washer.
  6.  
  7. Using a punch and a hammer, drive the pinion shaft lockpin from the ring gear side of the case. Remove the pinion shaft, both pinions, both side gears and the throughst washers.
  8.  



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Fig. Fig. 27: Removing the pinion shaft lock pin



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Fig. Fig. 28: Assembling pinion and side gears

  1. Clean and inspect the parts for damage and replace parts as necessary.
  2.  
  3. Assemble the pinion shaft, both pinions, both side gears and the throughst washers into the case.
  4.  
  5. Using a dial micrometer, hold a pinion and side gear toward the case and measure the backlash of the other side gear; it should be 0.05-0.20mm. If the backlash is not within specifications, replace the throughst washer.
  6.  



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Fig. Fig. 29: Installing pinion shaft locking pin



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Fig. Fig. 30: Differential assembly



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Fig. Fig. 31: Removing No. 1 and No. 2 shift inner lever

  1. Using a punch and a hammer, drive the pinion shaft lockpin into the ring gear side of the case.
  2.  
  3. Align the ring gear with the differential case, install a new locking plate and set bolts. Torque the bolts evenly, in several steps, to 71 ft. lbs.
  4.  
  5. Using a hammer and a punch, stake the locking plates.
  6.  

Stake a claw flush with the flat surface of the nut. For the claw contacting the protruding portion of the nut, stake only1/2on the tightening side.

  1. Using a press and the differential side bearing installer tool, press the differential side bearings onto the differential case.
  2.  

SHIFT AND SELECT LEVER



See Figures 32, 33 and 34



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Fig. Fig. 32: Shift forks and shaft assemblies

  1. Remove the shift/select lever assembly from the case.
  2.  
  3. Remove the E-ring and compression ring.
  4.  
  5. Using a pin punch and a hammer, drive the slotted spring pins from the No. 1 and No. 2 inner shift levers.
  6.  



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Fig. Fig. 33: Removing select inner shaft



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Fig. Fig. 34: Lever shaft and boot assembly

  1. Remove the No. 2 shift inner lever, the No. 1 shift inner lever and the shift interlock plate.
  2.  
  3. Using a pin punch and a hammer, drive the slotted spring pins from the select inner lever.
  4.  
  5. Remove the select inner lever, the compression spring and the spring seat.
  6.  
  7. Tap the snapring from the lever shaft and remove the lever shaft and boot.
  8.  
  9. Using a small prybar, pry the out seal and replace it.
  10.  
  11. Clean and inspect the parts for damage; replace the parts, if necessary.
  12.  
  13. Grease the shaft, install the boot and shaft to the control shaft cover.
  14.  

When installing the boot, be sure to position the boot's air bleed downward.

  1. Install the snapring, the spring seat, the compression spring and the select inner lever.
  2.  
  3. Using a pin punch and a hammer, drive in the slotted spring pin.
  4.  
  5. Align the interlock plate to the No. 1 inner shift lever and install it.
  6.  
  7. Install the No. 2 inner shift lever.
  8.  
  9. Using a pin punch and a hammer, drive in the slotted spring pins.
  10.  
  11. Install the compression spring, seat and E-ring.
  12.  

TRANSAXLE RE-ASSEMBLY



See Figures 35 through 39

  1. Install the magnet into the bottom of the case.
  2.  
  3. Install the oil receiver and the differential into the case.
  4.  
  5. To adjust the differential side bearing preload, perform the following procedures:
    1. Install the thinnest side bearing shim into the transaxle case.
    2.  
    3. Install the differential into the transaxle case.
    4.  
    5. Install the transaxle case and tighten the bolts to 22 ft. lbs.
    6.  
    7. Using the differential preload wrench and a torque wrench, measure the bearing preload; the new bearings should be 7-14 INCH lbs. or old bearings should be 4-9 INCH lbs.
    8.  
    9. If the preload is not correct, use the differential side bearing cup remover to remove the transaxle case side outer side bearing race. Select and install a different side bearing shim, install the side bearing outer race and the case. Torque the case bolts and check the preload.
    10.  
    11. After the preload has been adjusted, remove the transaxle case.
    12.  

  6.  

The preload will change about 2.6-3.5 inch lbs. with each shim thickness.

  1. Install the input and output shaft assemblies.
  2.  
  3. Install the shift forks and shift fork shafts by positioning the No. 1 and No. 2 shift forks into the No. 1 and No. 2 hub sleeve grooves. Insert the No. 1 fork shaft into the No. 1 shift fork hole.
  4.  



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Fig. Fig. 35: Checking the differential preload with GM tool. Use the chart to select the correct adjusting shims



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Fig. Fig. 36: Reverse shaft and idler gear alignment

  1. Insert both interlock balls into the reverse shift fork hole. Install the No. 3 fork shaft and the reverse shift fork.
  2.  
  3. Install the No. 2 fork shaft, the shift head and the bolts; tighten the bolts to 12 ft. lbs.
  4.  
  5. Install the snaprings.
  6.  
  7. Place the reverse shift fork pivot into the reverse shift arm and install the reverse shift arm into the transaxle case; the bolts should be tightened to 13 ft. lbs.
  8.  
  9. Install the reverse idler gear and shaft; align the gear mark with the case hole.
  10.  
  11. Apply Loctite® sealant No. 518 or equivalent to the front and main transaxle case mounting surfaces and assemble the cases. Tighten the main case-to-front case bolts to 22 ft. lbs.
  12.  



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Fig. Fig. 37: Apply sealant to mating surface of the front and main cases

  1. Install the balls, springs and seats into the lockball assembly holes. Apply sealant to the plugs and lockball assembly. Tighten the plugs to 18 ft. lbs. and the lockball assembly to 29 ft. lbs.
  2.  
  3. Install the reverse idler gear shaft and torque the lockbolt to 18 ft. lbs.
  4.  
  5. Install both bearing snaprings and the No. 2 fork shaft snapring.
  6.  
  7. Install the rear bearing retainer; tighten the bolts to 14 ft. lbs.
  8.  
  9. Use the proper installation tool and a hammer to drive the 5th driven gear onto the shaft.
  10.  
  11. Install the spacer, the needle bearing, the 5th gear and the synchronizer ring.
  12.  
  13. Install the clutch hub, the shifting keys and the key springs onto the hub sleeve
  14.  

When installing the shifting springs, position them under the shifting keys and position them so their gaps do not align with each other.

  1. Using the gear installation tool, drive the No. 3 hub sleeve, with the No. 3 shifting fork, and align the synchronizer ring slots with the shifting keys.
  2.  



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Fig. Fig. 38: Installing 5th gear; GM tools shown

  1. Using a dial indicator, measure the 5th gear throughst clearance; it should be 0.10-0.57mm.
  2.  
  3. Select and install a snapring which will allow minimum axial play, onto the output shaft.
  4.  



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Fig. Fig. 39: Selection chart for 5th gear snaprings

  1. Engage the 5th gear and install the locknut; tighten it to 87 ft. lbs. After installation, disengage the gear and stake the locknut.
  2.  
  3. Install the shifting fork bolt and tighten it to 12 ft. lbs.
  4.  
  5. Position a new gasket on the control shaft cover, install the shift/select lever and torque the bolts to 14 ft. lbs.
  6.  
  7. Install the bellcrank to the transaxle case and tighten the bolt to 22 ft. lbs.
  8.  
  9. Apply Loctite® No. 518 (or its equivalent) to the transaxle case, install the case cover and tighten the retaining bolts to 13 ft. lbs.
  10.  
  11. Install the front bearing retainer and tighten the bolts to 8 ft. lbs.
  12.  
  13. Apply lithium grease to the inside groove of the release bearing hub, the input shaft spline and the release fork contact surface. Install the release fork and the bearing.
  14.  
  15. Using the proper size socket, install and tighten the back-up light switch to 30 ft. lbs.
  16.  
  17. Install the speedometer driven gear.
  18.  
  19. Shift the transaxle and check it for smooth operation.
  20.  

 
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