GM Full-Size Trucks 1988-1998 Repair Information

Transmission

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REMOVAL & INSTALLATION



See Figures 1 and 2

It would be best to drain the transmission before starting.

  1. Disconnect the battery ground cable.
  2.  
  3. Remove the air cleaner.
  4.  
  5. If equipped, disconnect the detent or TV cable at the throttle lever.
  6.  
  7. On 4WD models, remove the transfer case shift lever knob and boot.
  8.  
  9. Raise and support the truck on jackstands.
  10.  
  11. Disconnect the shift linkage from the transmission.
  12.  
  13. If it is necessary to disconnect the fuel line, relieve the fuel system pressure. Disconnect the fuel lines.
  14.  
  15. Remove any skid plates that would interfere with transmission removal.
  16.  
  17. Drain the transmission fluid.
  18.  
  19. Remove the driveshaft(s), after matchmarking its/their flanges.
  20.  
  21. Detach the speedometer cable or Vehicle Speed sensor (VSS) connector, downshift cable, vacuum modulator line, shift linkage, throttle linkage, electrical wiring, the fluid cooler lines, or any other component that would interfere with transmission removal.
  22.  
  23. Remove the dipstick tube.
  24.  
  25. If necessary, remove the starter motor.
  26.  
  27. If necessary, disconnect the support bracket at the catalytic converter.
  28.  
  29. Support the transmission on a transmission jack and unbolt the transmission rear mount or the transfer case adapter from the crossmember.
  30.  
  31. Remove the crossmember.
  32.  
  33. Remove any transmission support braces. Note their exact positions for installation.
  34.  
  35. Remove the torque converter underpan, matchmark the flywheel and converter, and remove the converter bolts.
  36.  
  37. If necessary for clearance, move the exhaust system aside.
  38.  
  39. If necessary for clearance, disconnect the parking brake cable.
  40.  
  41. Remove the transfer case and the adapter.
  42.  
  43. Support the engine on a jack and lower the transmission slightly for access to the upper transmission-to-engine bolts.
  44.  
  45. Remove the transmission-to-engine bolts and pull the transmission back. Rig up a strap or keep the front of the transmission up so the converter doesn't fall out.
  46.  

To install:

Installation is the reverse of removal but please note the following important steps.

  1. Tighten the transmission-to-engine bolts to 35 ft. lbs. (47 Nm).
  2.  

Make sure that the torque converter-to-flexplate matchmarks are aligned, the torque converter is flush with the flywheel and the converter turns freely by hand.

  1. On all except 1996-98 models, tighten the converter bolts to 50 ft. lbs. (68 Nm).
  2.  
  3. On 1996-98 models, tighten the converter bolts to 46 ft. lbs. (63 Nm).
  4.  
  5. Tighten the transmission support brace bolts to 35 ft. lbs. (47 Nm).
  6.  
  7. On all except 1991-98 models, tighten the crossmember retainers to 35 ft. lbs. (47 Nm).
  8.  
  9. On 1991-98 models tighten the crossmember retainers to 56 ft. lbs. (77 Nm).
  10.  
  11. On 1988-94 4WD models, tighten the transfer case-to-transmission attaching bolts to 24 ft. lbs. (32 Nm) and the transfer case-to-frame bracket bolts to 35 ft. lbs. (47 Nm).
  12.  
  13. On 1995-98 4WD models, tighten the adapter-to-transfer case and adapter-to-transmission bolts to 33 ft. lbs. (45 Nm).
  14.  



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Fig. Fig. 1: Automatic transmission and related components-THM400, 4L60E and 4L80E



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Fig. Fig. 2: Automatic transmission and related components-THM700R4

 
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