GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Transmission

Print

REMOVAL & INSTALLATION



See Figures 1, 2 and 3

Manual transmission removal on most vehicles covered by this manual can be done through the following, fairly straightforward procedures. In most cases, the transmission can be removed leaving the bellhousing and the clutch assembly in position. The bellhousing on the 77.5mm 4-speed and MW2 (New Venture Gear) 5-speed is integral with the transmission casing and therefore must be unbolted in order to remove the transmission assembly. Of course, if the transmission is being removed for clutch replacement, the bellhousing must be removed anyway.

On many of the vehicles covered by this manual, the upper bellhousing-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.



Click image to see an enlarged view

Fig. Fig. 1: Catalytic converter hanger assembly under the transmission-common application

Vehicles Through 1988
2-WHEEL DRIVE
  1. Disconnect the negative battery terminal from the battery.
  2.  
  3. If the bellhousing is being removed with the transmission (77.5mm 4-speed) remove the starter. The 77mm 4-speed and 5-speed can be removed without removing the bellhousing.
  4.  
  5. Shift the transmission into Neutral. Remove the shift lever boot-to-console screws and slide the boot up the shift lever.
  6.  
  7. Remove the shift lever.
  8.  
  9. Raise and safely support the truck on jackstands. Remove the drain plug and drain the oil. Dispose of old oil properly at a reclamation center, such as a gas station or parts retailer.
  10.  
  11. Disconnect the speedometer cable and/or the electrical wiring connectors from the transmission.
  12.  
  13. Remove the driveshaft. Refer to the Driveline section if necessary.
  14.  
  15. Disconnect the exhaust pipe-to-exhaust manifold nuts and separate the exhaust pipe from the manifold.
  16.  
  17. On the 1982-83 models, disconnect the clutch cable from the clutch lever. On the 1984-91 models, remove the clutch slave cylinder from the clutch release lever. It can be secured out of the way without disconnecting the hydraulic line.
  18.  
  19. Position a floor jack under the transmission and support the transmission. Secure the jack to the transmission so it won't slip
  20.  
  21. Remove the transmission-to-crossmember mount bolts.
  22.  
  23. Remove the catalytic converter-to-chassis hanger bolts.
  24.  
  25. Remove the crossmember-to-chassis bolts and the crossmember from the vehicle.
  26.  
  27. If the bellhousing is being removed, remove the clutch cover from the front of the housing.
  28.  

On some vehicles, access to and removal of the upper bellhousing bolts may be difficult. Refer to the text at the beginning of thetransmission removal proceduresfor suggestions.

  1. Unbolt the bellhousing from the engine, or the transmission from the bellhousing and carefully roll the floor jack straight back away from the engine. Carefully lower it from the vehicle.
  2.  

To install

  1. Lightly coat the input shaft spline with high temperature or molybdenum grease. Don't use too much or the clutch disc will be ruined.
  2.  
  3. If the clutch was removed, make sure it is properly aligned or it will be impossible to install the transmission.
  4.  
  5. Put the transmission into high gear.
  6.  
  7. With the transmission properly placed behind the engine, turn the output shaft slowly to engage the splines of the input shaft into the clutch while pushing the transmission forward into place. Don't force it, the transmission will easily fall into place when everything is properly aligned.
  8.  
  9. On 4-cylinder engines with the 77.5mm transmission, torque the bellhousing-to-engine bolts to 25 ft. lbs. (34 Nm). On all others, torque the bolts to 55 ft. lbs. (75 Nm).
  10.  
  11. Install the cross member and torque the bolts to 25 ft. lbs. (34 Nm).
  12.  
  13. Install the support braces and catalyst hanger and torque the nuts and bolts to 35 ft. lbs. (47 Nm).
  14.  
  15. Install the clutch inspection cover and starter.
  16.  
  17. On 1984-91 models, install the slave cylinder and if necessary, attach the hydraulic line and bleed the system.
  18.  
  19. On earlier models, attach the clutch cable and push the pedal to test its operation.
  20.  
  21. Install the shift lever and boot.
  22.  
  23. Reassemble the exhaust system.
  24.  
  25. Install the driveshaft and refill the transmission with the proper oil.
  26.  
  27. Connect the wiring for the back-up lights and speed sensor, or the speedometer cable.
  28.  
  29. Remove the jackstands and lower the vehicle to the ground, then reconnect the battery.
  30.  



Click image to see an enlarged view

Fig. Fig. 2: View of the transmission crossmember (upper or forward of the 2 visible members)

4-WHEEL DRIVE
  1. Shift the transfer case into 4H .
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Raise and support the vehicle safely using jackstands. Remove the skid plate.
  6.  
  7. Drain the lubricant from the transfer case.
  8.  
  9. Mark the transfer case front output shaft yoke and driveshaft for assembly reference. Disconnect the front driveshaft from the transfer case.
  10.  
  11. Mark the rear axle yoke and driveshaft for assembly reference. Remove the rear driveshaft.
  12.  
  13. Disconnect the speedometer cable and vacuum harness at the transfer case. Remove the shift lever from the transfer case.
  14.  
  15. Remove the catalytic converter hanger bolts at the converter.
  16.  
  17. Raise the transmission and transfer case and remove the transmission mount attaching bolts. Remove the mount and catalytic converter hanger and lower the transmission and transfer case.
  18.  
  19. If the bellhousing is being removed, remove the clutch cover from the front of the housing.
  20.  

On some vehicles, access to and removal of the upper bellhousing bolts may be difficult. Refer to the text at the beginning of thetransmission removal proceduresfor suggestions.

  1. Unbolt the bellhousing from the engine, or the transmission from the bellhousing and carefully roll the floor jack straight back away from the engine. Carefully lower it from the vehicle.
  2.  

To install

  1. Lightly coat the input shaft spline with high temperature or molybdenum grease. Don't use too much or the clutch disc will be ruined.
  2.  
  3. If the clutch was removed, make sure it is properly aligned or it will be impossible to install the transmission.
  4.  
  5. Put the transmission into high gear.
  6.  
  7. With the transmission properly placed behind the engine, turn the output shaft slowly to engage the splines of the input shaft into the clutch while pushing the transmission forward into place. Don't force it, the transmission will easily fall into place when everything is properly aligned.
  8.  
  9. On 4-cylinder engines with the 77.5mm transmission, torque the bellhousing-to-engine bolts to 25 ft. lbs. (34 Nm). On all others, torque all the bolts to 55 ft. lbs. (75 Nm).
  10.  
  11. Install the crossmember and torque the bolts to 25 ft. lbs. (34 Nm).
  12.  
  13. Install the support braces and catalyst hanger and torque the nuts and bolts to 35 ft. lbs. (47 Nm).
  14.  
  15. Install the clutch inspection cover and starter.
  16.  
  17. On 1984-91 models, install the slave cylinder and if necessary, attach the hydraulic line and bleed the system.
  18.  
  19. On earlier models, attach the clutch cable and push the pedal to test its operation.
  20.  
  21. Install the transmission shift lever and transfer case shift linkage.
  22.  
  23. Reassemble the exhaust system.
  24.  
  25. Install the driveshafts. Note the alignment marks and make sure the shafts are installed the same way.
  26.  
  27. Refill the transmission and transfer case with the proper fluids.
  28.  
  29. Connect the wiring for the back-up lights and speed sensor, or the speedometer cable. Connect the transfer case vacuum lines.
  30.  
  31. Lower the vehicle to the ground and reconnect the battery.
  32.  



Click image to see an enlarged view

Fig. Fig. 3: Common transmission-to-engine mounting-New Venture Gear 3500 model shown

1989-93 Vehicles
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the shift lever. For details, please refer to the procedure earlier in this section.
  4.  
  5. Raise and support the vehicle safely using jackstands.
  6.  
  7. Disconnect the parking brake cable for clearance. Before disconnecting the cable, you may want to measure the adjustment or scribe marks to ease adjustment after installation.
  8.  
  9. Matchmark and remove the driveshaft. For details, please refer to the procedure later in this section.
  10.  
  11. If equipped, remove the skid plate.
  12.  
  13. On 4wd vehicles, remove the transfer case and shift lever. For details, please refer to the procedure later in this section.
  14.  
  15. Tag and disengage the necessary wiring connectors, including the reverse (backup) light switch and Vehicle Speed Sensor (VSS) connectors.
  16.  
  17. For 1992-93 4.3L engines, properly relieve the fuel system pressure, then disconnect the fuel lines at the engine.
  18.  
  19. Disconnect the exhaust pipes.
  20.  

On some vehicles, access to and removal of the upper bellhousing bolts may be difficult. Refer to thetext at the beginning of the transmission removal proceduresfor suggestions.

  1. Remove the slave cylinder from the transmission. If the cylinder can be repositioned with the hydraulics intact, simply support it out of the way, but make sure the line is not stretched, kinked or otherwise damaged. If necessary, disconnect the line and remove the cylinder completely.
  2.  
  3. Support the transmission carefully using a floor jack. If possible, secure the transmission to the jack to keep it from shifting suddenly and falling.
  4.  
  5. Remove the transmission mount retainers.
  6.  
  7. If necessary, remove the catalytic converter support hanger.
  8.  
  9. Disconnect or remove the necessary support braces.
  10.  
  11. If necessary, unbolt and remove the transmission crossmember.
  12.  
  13. Make sure the transmission is properly supported, then remove the transmission-to-bellhousing or transmission-to-engine bolts, as necessary.
  14.  
  15. Carefully pull the transmission assembly, straight back to disengage the input shaft splines, DO NOT allow the transmission to hang on the clutch. For 4.3L engines it may be necessary to rotate the transmission counterclockwise, then pull back and disengage it from the engine. Once the transmission is disengaged, slowly lower the jack and transmission to remove it from the vehicle.
  16.  

To install:
  1. Place a THIN coat of high-temperature grease on the main drive gear (input shaft) splines, then shift the transmission into height gear.
  2.  

For 4.3L engines, it may be necessary to rotate the transmission clockwise while inserting it to the clutch hub.

  1. Secure the transmission to the floor jack, then carefully raise it into position, directly behind the engine. Slowly insert the input shaft through the clutch. Rotate the output shaft slowly to engage the splines of the input shaft into the clutch while pushing the transmission forward into place. DO NOT force the transmission into position, the transmission will easily fall into place when everything is properly aligned.
  2.  
  3. Once the transmission is properly positioned, install the retaining bolts and tighten to 55 ft. lbs. (75 Nm).
  4.  
  5. If removed, install the crossmember to the vehicle.
  6.  
  7. Install or connect the necessary support braces.
  8.  
  9. If removed, install the catalytic converter support hanger.
  10.  
  11. Install the transmission mount bolts and tighten to 37 ft. lbs. (50 Nm).
  12.  
  13. Install the slave cylinder to the transmission. If the hydraulic line was disconnected, the system will have to be bled of air.
  14.  
  15. Connect the exhaust pipes.
  16.  
  17. For 1992-93 4.3L engines, connect the fuel lines at the engine.
  18.  
  19. Engage the necessary wiring harness connectors, including the reverse light switch and the VSS.
  20.  
  21. For 4wd vehicles, install the transfer case.
  22.  
  23. If equipped, install the skid plate.
  24.  
  25. Align and install the driveshaft.
  26.  
  27. Connect and adjust the parking brake cable.
  28.  
  29. Remove the jackstands and carefully lower the vehicle.
  30.  
  31. Install the shift lever.
  32.  
  33. Connect the negative battery cable.
  34.  

 
label.common.footer.alt.autozoneLogo