Pontiac Fiero 1984-1988 Repair Guide

5-Speed 76mm Isuzu (MT2) Overhaul

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DISASSEMBLY





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Fig. Fig. 1 Exploded view of the 5-speed (76mm) Isuzu transaxle gearshaft



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Fig. Fig. 2 Isuzu 5-speed (76mm) transaxle gearshaft component list



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Fig. Fig. 3 Exploded view of the differential assembly components



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Fig. Fig. 4 Components of the Isuzu 5-speed (76mm) transaxle shift mechanism



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Fig. Fig. 5 Use a ratchet and socket to remove the 5th gear retaining nut ...



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Fig. Fig. 6 ... then remove the 1st-5th gear detent spring and balls



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Fig. Fig. 7 Install tool J-35274 and remove the gear from the input shaft



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Fig. Fig. 8 Remove the reverse idle shaft bolt using a breaker bar and socket



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Fig. Fig. 9 Use a punch and hammer to drive out the 1-2 shift fork roll pin



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Fig. Fig. 10 Remove the input and output bearing races using the tools in the illustration

  1. Remove the transaxle and cradle assembly from the vehicle as outlined in the "Transaxle and Cradle" procedures in this section.
  2.  
  3. Remove the clutch release bearing and place the transaxle assembly in a holding fixture tool J-33366 or equivalent.
  4.  
  5. Remove the seven bolts from the rear cover and remove the cover.
  6.  
  7. Remove the shift control box and four bolts.
  8.  
  9. Using a screwdriver, shift the transaxle into gear. Remove the 5th gear drive and driven gear retaining nuts from the input and output shaft. Shift the transaxle into neutral, aligning the detents on the shift rails.
  10.  
  11. Remove the 1-2, 3-4, reverse-5 detent spring retaining bolts and balls.
  12.  
  13. Place the 5th gear synchronizer in neutral. Remove the roll pin at the 5th gear shift fork. Remove the 5th gear synchro hub, sleeve, roller bearing and gear with the fork as an assembly. Using tool No. J-35274, remove the 5th gear from the input shaft.
  14.  
  15. Remove the reverse idler shaft retaining bolt at the transaxle case.
  16.  
  17. Remove the collar and thrust washer from the output shaft using tool No. J-22888 and J-22888-30.
  18.  
  19. Remove the fourteen bolts retaining the transaxle case to the clutch housing and separate the two housings. Gently tap the clutch case with a rubber hammer.
  20.  
  21. Remove the reverse idle gear and idle shaft. Lift the 5th gear shaft, with the detent aligned facing the same way and remove the 5th and reverse shafts at the same time.
  22.  
  23. Using a punch and hammer, remove the roll pin from the 1-2 shift fork. Slide the 1-2 shaft upward to clear the housing and remove the fork and shaft.
  24.  
  25. Remove the input and output shafts with 3-4 shift fork and shaft as an assembly.
  26.  
  27. Remove the differential case assembly. Remove the reverse shift bracket with the four bolts and take the three interlock pins out.
  28.  
  29. Remove the rear bearing outer races from the case with tool No. J-24256-A and J-33370.
  30.  
  31. Remove the outer races for the input shaft front bearing, output shaft front and differential side bearings using a slide hammer.
  32.  
  33. Remove the input shaft seal and clutch shaft seal from the housing. Drive out the bushing toward the inside by the use of tool No. J-28412. Remove the fork assembly only when replacing the clutch fork assembly.
  34.  

Shaft Disassembly
INPUT SHAFT


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Fig. Fig. 11 Use tool J-22912-01 or its equivalent and a press to remove the input shaft front bearing

  1. Remove the front bearing using a press and tool No. J-22912-01.
  2.  
  3. Remove the rear bearing, 4th gear, 3rd/4th synchronizer and 3rd gear as an assembly.
  4.  
  5. Remove all other parts from the input shaft.
  6.  

OUTPUT SHAFT


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Fig. Fig. 12 Remove the front output bearing using tools J-22227A and J-33369 or their equivalents



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Fig. Fig. 13 Use a press to remove the collar, reverse gear and 1st gear from the output shaft

  1. Remove the front bearing using tool No. J-22227-A with J-33369 and a press.
  2.  
  3. Remove the rear bearing and 3rd/4th gear assemblies with a press.
  4.  
  5. Remove the key, 2nd gear, needle bearing and blocker rings.
  6.  
  7. Remove the collar, reverse gear and 1st gear as an assembly by the use of a press.
  8.  

DIFFERENTIAL DISASSEMBLY
  1. Remove the side bearing using a tool No. J-22888 and a puller leg kit.
  2.  
  3. Remove the ten ring gear retaining bolts and gear.
  4.  
  5. Using a screwdriver, pry off the speedometer drive gear. Do not use the old speedometer drive gear again.
  6.  
  7. Drive out the lock and cross pin.
  8.  
  9. Remove the pinion gears and thrust washers. Remove the side gears and thrust washers. Refer to the "Differential" assembly exploded view in the beginning of this section.
  10.  

Shaft Reassembly
INPUT SHAFT


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Fig. Fig. 14 Press the 3rd/4th sleeve, hub and collar after their inserts have been matched with the grooves on the blocker ring



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Fig. Fig. 15 Use tool J-33368 or its equivalent to install the input shaft front and rear bearings

Before assembling the shafts, apply a coat of specified lubricant to the thrust washers, all gears and washers.

  1. Install the needle bearings coated with white lithium grease to hold into place during reassembly. Install the 3rd gear and blocker ring.
  2.  
  3. Match the inserts of the 3rd/4th sleeve and hub with the grooves of the blocker ring and press the sleeve and hub and collar using tool No. J-33374 and a press.
  4.  
  5. Install the blocker ring and needle bearings. Install the 4th gear and thrust washer next. The thrust washer goes with the recessed area facing the 4th gear.
  6.  
  7. Install the front and rear bearings using tool No. J-33374 and a press.
  8.  

OUTPUT SHAFT

Before assembling the shafts, apply a coat of specified lubricant to the thrust washers, all gears and washers.

  1. Install the thrust washer, thrust needle bearings coat with grease and 1st gear and blocker ring.
  2.  
  3. Match the inserts of the sleeve and hub with the grooves in the blocker ring and press the sleeve and hub together with the collar using tool No. J-8853-01 and a press.
  4.  
  5. Install the blocker ring needle bearings and 2nd gear. Install the key on the key groove next.
  6.  
  7. Apply oil to 3rd/4th gear and match the key with the key groove and fit the key together with the rear bearing. Using tool No. J-33374 and a press, press the bearing onto the shaft.
  8.  
  9. Press the front bearing onto the shaft using tool No. J-33368 and a press.
  10.  

DIFFERENTIAL ASSEMBLY

Before assembling the shafts, apply a coat of specified lubricant to the thrust washers, all gears and washers.

  1. Install the two side gears on the differential case together with the thrust washers.
  2.  
  3. Position the two thrust washers and pinion gears opposite of each other. Install them in their positions by turning the side gears.
  4.  
  5. Insert the cross pin and make sure the gear backlash is within the rated range of 0.03-0.08mm.
  6.  
  7. Install the lock pin and stake it when the correct backlash is achieved.
  8.  
  9. Heat the speedometer drive gear to about 203°F (95°C) with a hot oil dryer or equivalent. Install the gear on the differential.
  10.  
  11. Install the ring gear onto the differential case and install the ten new bolts. Torque the bolts to 73-79 ft. lbs. (98-107 Nm) in a diagonal sequence.
  12.  
  13. Install the side bearings on the differential case using an arbor press.
  14.  

Case Reassembly


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Fig. Fig. 16 Ensure that the interlock pin is in the 5th gear shifter shaft before installation



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Fig. Fig. 17 Location of the bearing gauge positions



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Fig. Fig. 18 Bearing spacer and gauge positioning



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Fig. Fig. 19 The 5th gear, shift fork and other components should be in this position



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Fig. Fig. 20 Location of the stopper cam alignment marks



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Fig. Fig. 21 Use a torque wrench to measure the input shaft rotating torque

Before assembling the shafts, apply a coat of specified lubricant to the thrust washers, all gears and washers.

  1. Install a new input shaft seal using tool J-26540.
  2.  
  3. Install the front outer bearing races for the input shaft, output shaft and differential into the clutch housing. Press the input and output races into the housing using tools J-33371, J-8092, J-7817, J-8611-01 and an arbor press.
  4.  
  5. Apply grease to the interlock pins and install them on the clutch housing.
  6.  
  7. Install the reverse shift bracket onto the clutch housing. Use the 3rd/4th shift rod to align the bracket to housing. Install the retaining bolts and torque to 11-16 ft. lbs. (15-22 Nm). Make sure the rod operates properly.
  8.  
  9. Install the differential assembly first, then install the input and output shaft with the 3rd/4th shift fork and shaft as an assembly into the clutch housing. Make sure the interlock pin is in the 3rd/4th shifter shaft before installing.
  10.  
  11. The 3rd/4th shift shaft is installed into the raised collar of the reverse shift lever bracket.
  12.  
  13. Install the 1-2 shift fork onto the synchronizer sleeve and insert the shifter shaft into the reverse shift lever bracket. Align the hole in the fork with the shaft and install a new roll pin. Stake the roll pin after installation.
  14.  
  15. Install the reverse lever onto the shift bracket. Install the 5th/reverse shifter shaft with the reverse shift lever. Make sure the interlock pin is in the 5th gear shifter shaft before installing.
  16.  
  17. Install the reverse idler shaft with the gear into the clutch housing. The reverse lever must be engaged with the collar on the gear.
  18.  
  19. Measure and determine the shim size using tool J-33373 as follows:
  20.  
    1. Position the outer bearing races on the input, output and differential bearings. Position the shim selection gauges on the bearing races. The three gauges are identical.
    2.  
    3. Place seven spacers provided with tool J-33373 evenly around the perimeter of the clutch housing.
    4.  
    5. Install the bearing and shim retainer on the transaxle case. Torque the screws to 11-16 ft. lbs. (15-22 Nm). After torquing the screws, stake the screws to the retaining plate.
    6.  
    7. Position the transaxle case over the gauges and on the spacers. Install the seven bolts provided with the tool kit and tighten the bolts alternately until the case is seated on the spacers. Torque the bolts to 10 ft. lbs. (15 Nm).
    8.  
    9. Rotate the gauges to seat the bearings. Rotate the differential case through three revolutions in each direction.
    10.  
    11. With the three gauges compressed, measure the gap between the outer sleeve and the base pad using the available shim sizes in the following "Preload Shim Size" chart. The input shaft shim should be one size smaller than the largest shim that will fit in the gap. The differential should use a shim three sizes larger than that which will smoothly fit in the gap. The output shaft should use the largest shim that can be placed into the gap and drawn through without binding.
    12.  
    13. When each of the shims have been selected, remove the transaxle case, seven spacers and three gauges.
    14.  

  21. Position the shim selected for the input, output and differential into the bearing race bores in the transaxle case.
  22.  
  23. Install the rear input shaft bearing race using tool J-24256 with J-8092.
  24.  
  25. Install the rear output shaft bearing race using tool J-33370 with J-8092.
  26.  
  27. Install the differential case bearing race using tool J-8611-01 with J-8092 and a press. Press in the bearing until it is in its bore.
  28.  
  29. Apply a 1 / 8 inch bead of Loctite® #514 to the mating surfaces of the clutch housing and transaxle case.
  30.  
  31. Make sure the magnet is installed into the case.
  32.  
  33. Install the transaxle case to the clutch housing and the reverse idler shaft bolt into the case. Torque the bolt to 22-33 ft. lbs. (30-45 Nm).
  34.  
  35. Install the fourteen transaxle case bolts and torque in a diagonal sequence to 22-33 ft. lbs. (30-45 Nm).
  36.  
  37. Install the new drive axle seals using tools J-26938 and J-29130.
  38.  
  39. Install the thrust washers and collar to the output shaft using tool J-33374.
  40.  
  41. Install the 5th gear to the input shaft with the needle bearings, 5th gear, blocker ring, hub/sleeve assembly with the shift fork in its groove and the back plate on the output shaft. Align the shift fork on the shifter shaft and install the new roll pin.
  42.  
  43. Install the detent balls and detent springs for the reverse, 1st/2nd, 3rd/4th and 5th speeds. Install the retaining bolts and torque to 15-21 ft. lbs. (21-29 Nm).
  44.  
  45. Apply Loctite® # 262 or equivalent to the threads of the input and output shafts. Carefully wipe any oil from the threads. Do not allow any Loctite® to run into the splines of the 5th gear. Install the new retaining nuts and torque to 87-101 ft. lbs. (118-137 Nm). Stake the nuts after reaching final torque.
  46.  
  47. Assemble the control box as follows:
  48.  
    1. Assemble the stopper cam and internal lever. Make sure the serrations on the stopper cam and internal lever are aligned.
    2.  
    3. Install the stopper cam and internal lever to the shift lever.
    4.  
    5. Align the stopper cam alignment mark with the center on the internal lever.
    6.  
    7. Check to see that the reverse inhibitor mechanism operates properly.
    8.  
    9. Use a new roll pin to attach the internal lever during assembly.
    10.  

  49. Install the gasket and control box on the transaxle case and torque the four bolts to 11-16 ft. lbs. (15-22 Nm).
  50.  
  51. Make sure the transaxle shifts properly before installing rear cover.
  52.  
  53. Install the gasket and rear cover with the seven bolts. Torque the bolts to 11-16 ft. lbs. (15-22 Nm).
  54.  
  55. Install the clutch fork assembly if it has been removed. Install the bushing into the upper hole using tool J-28412 and install the oil seal next using tool J-28406.
  56.  
  57. Install the clutch release bearing as outlined in the "Clutch" procedures in this section. Measure the rotating torque on the input shaft. The rotating torque should be less than 7 inch.lb.
  58.  

 
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