GM Blazer/Jimmy/Typhoon/Bravada 1983-1993 Repair Guide

Transmission

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REMOVAL & INSTALLATION



On many of the vehicles covered by this information, the upper transmission-to-engine bolts (especially the upper left) may be difficult to access and withdraw due to the close proximity of the cowl sheet metal. Even if a wrench fits over the bolt, there may be insufficient room to fully unthread it. The factory recommended procedure to access these bolts is to remove the left body mount bolt(s) from under the cab and loosen the radiator support mounting, then carefully jack the body up off the frame until sufficient clearance exists. Place wooden blocks between the body and frame to support the body (this is to prevent damage and for SAFETY) during service. In some cases, this may be unnecessary if the engine will pivot downward sufficiently on the motor mount to allow bolt access or if the motor mounts are removed and the engine is supported using a lifting device. BUT DO NOT try this if it appears that the mounts will be damaged by the stress. Also, be sure the engine is properly supported at ALL times and that no components will be damaged. Watch that the distributor does not contact the cowl and that the cooling fan remains clear of the radiator and shroud assembly. When in doubt, unbolt and raise the body for access.

Vehicles Through 1991

See Figure 1

The following procedure requires the use of the Torque Converter Holding Strap tool No. J-21333 or equivalent.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly.
  4.  
  5. Disconnect the Throttle Valve (TV) cable from the throttle linkage.
  6.  

If equipped with a 4-cylinder engine, remove the upper starter bolt.

  1. Raise and support the truck safely using jackstands.
  2.  
  3. Remove the driveshaft-to-differential bolts, then slide the driveshaft from the transmission (2wd) or transfer case (4wd).
  4.  

On 4WD vehicles, the transfer case will be removed along with the transmission as an assembly.

  1. Disconnect the speedometer cable, the dipstick tube (and seal), the shift linkage (transmission and transfer case, on 4wd) and the electrical wiring connectors from the transmission.
  2.  
  3. Remove the transmission-to-catalytic converter support brackets and the engine-to-transmission support brackets, if equipped.
  4.  
  5. Remove the transmission-to-crossmember nuts/bolts, slide the crossmember rearward and remove it from the vehicle.
  6.  
  7. Remove the torque converter cover, then match-mark the torque converter-to-flywheel.
  8.  
  9. Remove the torque converter-to-flywheel bolts. Using the converter holding strap tool No. J-21333 or equivalent, secure the torque converter to the transmission.
  10.  
  11. Using a transmission jack, position and secure it to the underside of the transmission, then take up the transmission's weight.
  12.  

On some vehicles, access to and removal of the upper transmission housing retaining bolts may be difficult. Refer to the text at the beginning of the transmission removal procedures for suggestions.

  1. Remove the transmission-to-engine mount bolts and the mounts from the vehicle.
  2.  
  3. Lower the transmission slightly to gain access to the fluid cooler lines, then disconnect and cap the fluid lines.
  4.  



Click image to see an enlarged view

Fig. Fig. 1: Early model automatic transmission mounting

  1. Disconnect the Throttle Valve (TV) cable from the transmission.
  2.  
  3. Position a floor jack or jackstand under the engine and support it.
  4.  
  5. Remove the transmission-to-engine bolts and then the transmission from the engine; pull the transmission rearward to disengage it and lower it from the truck.
  6.  

When removing the transmission, be careful not to allow the transmission to hang from the pilot shaft, as it could bend.

To install:
  1. Carefully position the transmission behind the engine and push it forward to engage the pilot shaft.
  2.  
  3. Install the transmission-to-engine bolts and tighten to specification:
  4.  
  5. 1.9L engine: 25 ft. lbs. (35 Nm)
  6.  
  7. 2.5L and 2.8L engines through 1988: 55 ft. lbs. (75 Nm)
  8.  
  9. 2.5L and 2.8L engines - 1989: 75 ft. lbs. (101 Nm)
  10.  
  11. Connect the fluid cooler lines and the TV cable.
  12.  
  13. Install and tighten the transmission mount bolts. Make sure the torque converter turns freely by hand.
  14.  
  15. Install and tighten the crossmember bolts.
  16.  
  17. Install all the converter-to-flywheel bolts finger tight, then tighten the bolts to 35 ft. lbs. (50 Nm) for vehicles through 1988 or to 32 ft. lbs. (84 Nm) for 1989-91 vehicles. Install the converter cover.
  18.  
  19. Install the transmission-to-engine bracket bolts, if equipped.
  20.  
  21. Install the catalyst support bracket.
  22.  
  23. Install the dipstick tube, speedometer cable and wiring.
  24.  
  25. Attach and adjust the shift linkage as required.
  26.  
  27. Install the driveshaft(s).
  28.  
  29. On 4-cylinder engines, install the starter bolt.
  30.  
  31. Remove the jackstands and carefully lower the vehicle, then connect the TV cable and adjust as necessary.
  32.  
  33. Install the air cleaner assembly and connect the negative battery cable.
  34.  
  35. Immediately refill the transmission with fluid, then check the level as described in General Information & Maintenance of this guide.
  36.  

1992-93 Vehicles
EXCEPT TYPHOON

See Figure 2

  1. Properly relieve the fuel system pressure, then disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly. If equipped (4L30 model) disconnect the TV cable from the TBI unit.
  4.  
  5. Raise and support the vehicle safely using jackstands.
  6.  
  7. Drain the transmission fluid. For details, please refer to the pan procedure located earlier in this section or in General Information & Maintenance of this guide.
  8.  
  9. Disconnect the shift linkage from the transmission.
  10.  
  11. Disconnect and remove the fuel lines.
  12.  
  13. Matchmark and remove the front (if applicable) and rear driveshafts.
  14.  
  15. Remove the support bracket at the catalytic converter. Remove any components necessary for clearance.
  16.  
  17. Support the transmission assembly using a floor jack.
  18.  
  19. Remove the transmission crossmember. Take care not to stretch or damage any cables or wiring when attempting to remove the crossmember.
  20.  
  21. Lower the transmission slightly for access, then remove the dipstick tube and seal. Cover or plug the opening in the transmission housing to prevent system contamination.
  22.  
  23. Disengage the speedometer harness connector and the vacuum modulator line, if equipped.
  24.  



Click image to see an enlarged view

Fig. Fig. 2: Transmission and components - 1992-93 4L30

  1. Disengage the necessary electrical wiring connectors from the transmission assembly.
  2.  
  3. Disconnect the transmission fluid cooler lines. Plug or cap all openings to prevent system contamination or excessive fluid spillage.
  4.  
  5. On 4wd vehicles, disengage the transfer case shifter and position it aside.
  6.  
  7. Remove the transmission support braces. Be sure to tag or note the location of all support braces as they must be installed in their original positions.
  8.  
  9. Remove the torque converter housing cover.
  10.  
  11. Matchmark the flywheel-to-torque converter relationship, then remove the retaining bolts.
  12.  
  13. Support the engine using a jackstand and a block of wood.
  14.  
  15. Remove the transmission-to-engine retaining bolts. Note the positions of any brackets or clips and move them aside.
  16.  
  17. Using the floor jack, slide the transmission straight back off the locating pins. Be careful not to drop the torque converter, then as soon as access is possible, install a torque converter retaining strap.
  18.  
  19. Carefully lower the transmission from the vehicle.
  20.  

To install:
  1. Make sure the torque converter is properly seated and a retaining strap is installed.
  2.  
  3. Using the floor jack, carefully raise the transmission into position in the vehicle, then remove the converter retaining strap. Slide the transmission straight onto the locating pins while aligning the marks on the flywheel and torque converter.
  4.  

The converter must be flush on the flywheel and rotate freely by hand.

  1. Install the transmission-to-engine retainers, taking care to properly reposition all brackets, clips and harness, as noted during removal. The retainers should not be torqued yet. Do NOT install the dipstick tube or transmission support brace screws at this time.
  2.  
  3. Install and finger-tighten the converter bolts, then tighten them to 50 ft. lbs. (38 Nm).
  4.  
  5. Remove the jackstand from the engine.
  6.  
  7. Install the converter housing cover.
  8.  
  9. Install the transmission support braces as noted during removal.
  10.  
  11. On 4wd vehicles, connect the transfer case shifter assembly.
  12.  
  13. Uncap the openings, then connect the transmission cooler lines. Be careful not to twist or bend the lines.
  14.  
  15. If equipped, connect the vacuum modulator line.
  16.  
  17. Engage the speedometer harness connector and the remaining electrical wiring to the transmission housing.
  18.  
  19. Uncover the opening in the transmission housing and position a new seal, then install the dipstick tube.
  20.  
  21. Tighten the transmission-to-engine retainers and the dipstick tube retainer, then tighten the bolts to 23 ft. lbs. (32 Nm).
  22.  
  23. Raise the rear of the transmission (taking care not to pinch or damage any cables, wires or components), then install the crossmember. Secure the transmission mount and any components which were removed for access.
  24.  
  25. Remove the floor jack from the transmission, then install the catalytic converter bracket.
  26.  
  27. Align and install the front (if equipped) and rear driveshafts.
  28.  
  29. Connect the fuel lines.
  30.  
  31. Connect the shift linkage and adjust, as necessary.
  32.  
  33. Refill the transmission using fresh fluid. Refer to General Information & Maintenance of this guide for fluid recommendations, capacities and level checking.
  34.  
  35. Remove the jackstands and carefully lower the vehicle.
  36.  
  37. If equipped, engage the TV cable, then check and adjust, as necessary.
  38.  
  39. Connect the negative battery cable, then check for proper operation.
  40.  

TYPHOON

See Figure 3

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle using jackstands.
  4.  
  5. Drain the fluid from the transfer case.
  6.  
  7. Remove the transfer case from the vehicle. For details, please refer to the procedures located later in this section.
  8.  
  9. Loosen and remove the retainers, then remove the torque converter cover.
  10.  
  11. Disengage the shift control cable from the transmission.
  12.  
  13. Remove the bolt and retaining clip, then reposition the fuel lines and speed sensor harness.
  14.  
  15. Disconnect the TV cable.
  16.  
  17. Remove the retaining nuts, then disconnect the oil cooler lines from the transmission.
  18.  
  19. Disconnect the vent hose by removing the retaining strap, then pulling the hose through the clip.
  20.  



Click image to see an enlarged view

Fig. Fig. 3: Transmission mounting and components - Typhoon

  1. Remove the dipstick from the oil filler tube. Remove the filler tube retaining bracket and bolt, then carefully pull the tube from the transmission. Keep track of the oil seal located on the base of the tube.
  2.  
  3. Loosen the nuts from the transmission-to-engine studs located on the right side of the housing, then remove the bracket.
  4.  
  5. Make sure the transmission is securely supported by a floor jack, then remove the engine-to-transmission bolts and studs.
  6.  
  7. Remove the transmission by carefully pulling the assembly back and, once it is disengaged from the converter, lowering it from the vehicle.
  8.  

To install:
  1. Carefully raise the transmission into position using the floor jack. Engage the transmission to the converter while positioning it to the engine.
  2.  
  3. Install the transmission-to-engine retainers. Tighten the bolts and studs to 35 ft. lbs. (47 Nm).
  4.  
  5. Position the bracket over the studs on the right side of the housing, then install the retaining nuts and tighten to 22 ft. lbs. (30 Nm).
  6.  
  7. Check the filler tube seal for damage and replace, as necessary. With the seal positioned in the transmission housing, carefully install the filler tube through the seal and into the transmission. Install the bracket bolt and clip, then install the dipstick to the tube.
  8.  
  9. Connect the vent hose by pulling it through the clip, then inside the strap.
  10.  
  11. Connect the oil cooler lines to the transmission then tighten the retaining nuts to 13 ft. lbs. (22 Nm).
  12.  
  13. Connect the TV cable and adjust, as necessary.
  14.  
  15. Reposition and secure the fuel lines and speed sensor harness using the clip and retaining bolt.
  16.  
  17. Connect the shift control cable and adjust, as necessary.
  18.  
  19. Install the torque converter cover and secure using the retainers.
  20.  
  21. Install the transfer case assembly.
  22.  
  23. Remove the jackstands and carefully lower the vehicle, then fill the transfer case with fluid.
  24.  
  25. Connect the negative battery cable and check the transmission fluid.
  26.  

 
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