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

Transfer Case

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REMOVAL & INSTALLATION



See Figures 1, 2, 3 and 4

Vehicles Through 1991
  1. Disconnect the negative battery cable.
  2.  
  3. Shift the transfer case into the 4wd High range.
  4.  
  5. Raise and support the vehicle safely using jackstands.
  6.  
  7. If equipped, remove the skid plate bolts and remove the skid plate from under the transmission/transfer case assembly.
  8.  
  9. On Model 231 transfer cases, remove the plug and drain the transfer case fluid.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: It is recommended that the fluid be drained from most transfer cases before removal



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Fig. Fig. 2: During installation, remember to remove the filler plug to check the level and, if necessary, add fluid

  1. Matchmark and remove the front and rear driveshafts from the transfer case.
  2.  
  3. Disconnect the speedometer cable(s), the vacuum harness and/or the electrical connectors, as necessary.
  4.  
  5. Disconnect the shift linkage from the case. If necessary for access from above, remove the center console from the vehicle.
  6.  
  7. Remove the catalytic converter front bracket bolts, then loosen the front converter clamp.
  8.  
  9. Support the transmission using a floor jack, then remove the transmission rear mounting bolts.
  10.  
  11. Carefully raise the transmission/transfer case assembly and remove the catalytic converter front bracket, then lower the assembly. Position a support (such as a jackstand) to keep the transmission in place.
  12.  
  13. Reposition the floor jack to support the transfer case, then remove transfer case retaining bolts. On vehicles equipped with automatic transmissions, remove the bolts from the shift lever bracket and position the bracket aside. This will permit access to the upper left transfer case attaching bolt.
  14.  
  15. Carefully lower the transfer case from the vehicle, then remove all traces of the old gasket from the mating surface.
  16.  

To install:
  1. Use a new transfer case-to-transmission gasket and mount the unit to the transmission. Torque the bolts to 23 ft. lbs. (31 Nm).
  2.  
  3. If removed, install the shift lever bracket bolts.
  4.  
  5. Remove the floor jack from the transfer case, then reposition the jack under the transmission. Remove the transmission support.
  6.  
  7. Raise the transmission/transfer case assembly in order to install the catalytic converter front hanger.
  8.  
  9. Once the converter front bracket is positioned, lower the assembly and remove the floor jack. Secure the transmission rear mounting bolts and the converter front bracket bolts. Don't forget to tighten the converter clamp.
  10.  
  11. Connect the transfer case shift linkage at the case, then check and adjust, as necessary. If removed, install the center console.
  12.  
  13. Connect the speedometer cable(s), vacuum harness and/or electrical wiring, as necessary.
  14.  
  15. Align and install the driveshafts.
  16.  
  17. Make sure the truck is level, then remove the filler plug to check the transfer case fluid level. If necessary, add fluid, then install the plug. For details concerning fluid recommendations and level checking, please refer to Chapter 1 of this manual.
  18.  
  19. If equipped, install the skid plate.
  20.  
  21. If not done already, remove the jackstands and lower the vehicle.
  22.  
  23. Connect the negative battery cable.
  24.  



Click image to see an enlarged view

Fig. Fig. 3: When equipped, the skid plate must be removed for access-late model shown



Click image to see an enlarged view

Fig. Fig. 4: Common transfer case mounting to automatic and manual transmissions

1992-93 Vehicles
  1. Disconnect the negative battery cable.
  2.  
  3. Shift the transfer case into the 4wd High range.
  4.  
  5. Raise and support the vehicle safely using jackstands.
  6.  
  7. If equipped, remove the skid plate bolts, then remove the skid plate from under the transmission/transfer case assembly.
  8.  
  9. Remove the plug and drain the transfer case fluid.
  10.  
  11. Matchmark and remove the front and rear driveshafts from the transfer case.
  12.  
  13. Tag and disconnect the vacuum lines and/or the electrical connectors, as equipped.
  14.  
  15. If applicable, disconnect the transfer case shift rod from the case.
  16.  
  17. If applicable, remove the support brace-to-transfer case bolts.
  18.  
  19. Support the transfer case using a floor jack, then remove the transfer case-to-transmission retaining bolts
  20.  
  21. Slide the transfer case rearward and off the transmission output shaft, then careful lower it from the vehicle.
  22.  
  23. Remove all traces of old gasket material from the mating surfaces.
  24.  

To install:
  1. Using the floor jack, carefully raise the transfer case into position behind the transmission. Position a new gasket, using sealer to hold it in position, then slide the transfer case onto the transmission output shaft.
  2.  
  3. Install the transfer case-to-transmission retaining bolts, then tighten to 24 ft. lbs. (33 Nm).
  4.  
  5. If equipped, install the support brace bolts and tighten to 35 ft. lbs. (47 Nm).
  6.  
  7. Remove the floor jack from the transfer case.
  8.  
  9. If equipped, connect the shift rod to the case.
  10.  
  11. Engage the vacuum lines and/or electrical connections, as necessary.
  12.  
  13. Align and install the front and rear driveshafts.
  14.  
  15. Make sure the truck is level, then properly refill the transfer case through the filler plug. For details, please refer to Chapter 1 of this manual.
  16.  
  17. If equipped, install the skid plate.
  18.  
  19. If not done already, remove the jackstands and carefully lower the vehicle.
  20.  
  21. Connect the negative battery cable.
  22.  

 
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