GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 3289-20 Holding Fixture
    • J 23907 Slide Hammer with Bearing Adapter
    • J 26941 Bushing and Bearing Remover - 3-4 inch
    • J 45380 Transfer Case Rear Bushing Remover and Installer
    • J 45759 Assembly Fixture

    Object Number: 824069  Size: SH

    Important: The transfer case has manufacturing design changes for this model year. The transfer case could be built with either 1st design components or 2nd design components. When the different design components affect disassemble procedures, follow the procedures for that design level. The changes are for manufacture purposes only and do not enhance the performance of the transfer case. The following are the 2nd design components:

       • High/low planetary carrier changed from 4 pinion gears to 3 pinions with the transmission RPO M30.
       • The clutch hub is a different design with the clutch pressure plate inner part of the hub.
       • The clutch oil restrictor plate is included with the clutch hub and not serviced separately.
       • The clutch apply plate is a different design.
       • The oil pump suction pipe is nylon and the oil pump screen is serviced only with the pipe.

  1. Attach the J 45759 to the transfer case using the adapter studs. All of the transfer case disassembly procedures can be performed with the case mounted to the J 45759 .

  2. Object Number: 819573  Size: SH
  3. Mount the J 3289-20  (1) to a sturdy workbench.
  4. Install the J 45759  (2) into J 3289-20  (1) and secure with pivot pin.

  5. Object Number: 857299  Size: SH
  6. Remove the fill plug (1) and the drain plug (2) and drain the transfer case fluid.

  7. Object Number: 857301  Size: SH
  8. Remove the connector, for the actuator encoder motor wiring harness, from the bracket.
  9. Remove the actuator encoder motor mounting bolts.
  10. Remove the actuator encoder motor assembly.
  11. Remove the actuator insulator gasket.

  12. Object Number: 857304  Size: SH
  13. Remove the plastic vent from the case; a NEW aluminum vent must be installed during assembly.

  14. Object Number: 1226851  Size: SH
  15. Remove the rear vehicle speed sensors (VSS).

  16. Object Number: 662047  Size: SH
  17. Remove the front VSS.

  18. Object Number: 1226852  Size: SH
  19. Remove the access hole plug.

  20. Object Number: 678215  Size: SH

    Notice: Do not damage the sealing surfaces of the transfer cases or the shafts when prying the seals for removal. Damaging the sealing surface may cause leakage or require replacement of the damaged component.

  21. Remove the input shaft seal by prying it out of the front case.

  22. Object Number: 715670  Size: SH
  23. Remove the rear output shaft seal.

  24. Object Number: 801274  Size: SH
  25. Inspect the rear output shaft bushing for scoring or wear.
  26. Remove the rear output shaft bushing using the J 45380 .
  27. 16.1. Install the finger section of the J 45380 in front of the bushing.
    16.2. Install the tube and forcing screw assembly to the finger section. Ensure the forcing screw is backed out.
    16.3. Using a wrench on the forcing screw, remove the rear output shaft bushing.

    Object Number: 1226857  Size: SH

    Important: The magnesium transfer cases are using new style bolts that have a cup style washer. The cup washer is only available with the bolt. If the cup washer is not damaged, the bolt can be used again.

  28. Remove the transfer case retaining bolts and washers.
  29. Mark the location of any brackets.


    Object Number: 695581  Size: SH

    Notice:  Do not nick, scratch or damage the sealing surface. The sealing surface is a machined surface. Damage to the machined surface can cause leakage.

  30. Insert a flat-blade screwdriver into the slot on the left side of the transfer case.

  31. Object Number: 695583  Size: SH
  32. Insert a flat-blade screwdriver into the slot on the right side of the transfer case.
  33. With equal pressure, press down on the screwdrivers in order to separate the front case half and the rear case half.

  34. Object Number: 649760  Size: SH
  35. Insert a pair of snap ring pliers and release the outer retaining ring for the rear output shaft bearing.

  36. Object Number: 163737  Size: SH
  37. Remove the rear case half from the front case half.

  38. Object Number: 724251  Size: SH
  39. Remove the oil pump wear sleeve, a new wear sleeve is required.

  40. Object Number: 701586  Size: SH
  41. Remove the rear output shaft rear bearing retaining ring.

  42. Object Number: 701589  Size: SH
  43. Remove the rear output shaft rear bearing.

  44. Object Number: 701592  Size: SH
  45. Remove the rear output shaft speed sensor reluctor wheel.

  46. Object Number: 163872  Size: SH
  47. If 1st design, disconnect the oil pump suction pipe from the oil pump screen.
  48. If 1st design, remove the oil pump screen from the front case half.
  49. If 1st design, remove the oil pump suction pipe from the oil pump inlet hole.

  50. Object Number: 1348893  Size: SH
  51. If 2nd design, remove the oil pump suction pipe assembly. Do not remove the screen from the pipe.

  52. Object Number: 163856  Size: SH
  53. Remove the magnet.

  54. Object Number: 886580  Size: SH
  55. Remove the oil pump wave spring.
  56. Remove the oil pump assembly.

  57. Object Number: 163888  Size: SH
  58. Remove the oil pump suction pipe O-ring from the oil pump.

  59. Object Number: 701617  Size: SH
  60. Remove the drive sprocket retaining ring.

  61. Object Number: 857307  Size: SH
  62. Remove the driven sprocket retaining ring.

  63. Object Number: 163905  Size: SH

    Important: If the chain and sprockets are to be used again, mark the relationship of the chain to the sprockets in order to mark the wear patterns.

  64. Remove the chain and sprockets.
  65. Remove the chain from the drive sprocket and driven sprocket.

  66. Object Number: 701622  Size: SH
  67. Remove the rear output shaft assembly.
  68. Mount the rear output shaft assembly, with the front end up, in a soft-jaw vise.

  69. Object Number: 1348894  Size: SH
  70. Remove the clutch assembly retaining ring. Push down on the clutch apply plate to access the retaining ring.

  71. Object Number: 857309  Size: SH
  72. If 1st design, remove the clutch apply plate assembly.
  73. If 1st design, remove the clutch return spring.

  74. Object Number: 1349232  Size: SH
  75. If 2nd design, remove the clutch apply plate assembly.
  76. If 2nd design, remove the clutch return spring.

  77. Object Number: 2040336  Size: SH
  78. If 1st design, remove the clutch apply plate bearing and inner support from the clutch apply plate.

  79. Object Number: 1348896  Size: SH
  80. If 2nd design, remove the clutch apply plate bearing and inner support from the clutch apply plate.

  81. Object Number: 801281  Size: SH
  82. Inspect the bearing for being faulty. Refer to Transfer Case Cleaning and Inspection .
  83. If the bearing is faulty, using a hydraulic press and a suitable adapter, remove the clutch apply plate bearing from the clutch bearing inner support.
  84. Discard the bearing after removal.

  85. Object Number: 857310  Size: SH
  86. Remove the clutch hub retaining ring.

  87. Object Number: 857312  Size: SH

    Important: Do not remove the oil restrictor plate on the 2nd design clutch hub. The oil restrictor plate is only serviced with the clutch hub.

  88. If 1st design, remove the clutch hub oil restrictor plate.
  89. Remove the clutch housing and hub assembly from the rear output shaft.

  90. Object Number: 801283  Size: SH
  91. Turn the clutch assembly over on a workbench.
  92. If 1st design, remove the clutch housing.
  93. If 1st design, remove the clutch hub.
  94. If 1st design, remove the clutch pressure plate inner.

  95. Object Number: 1348897  Size: SH
  96. If 2nd design, remove the clutch housing.
  97. If 2nd design, remove the clutch hub.

  98. Object Number: 670237  Size: SH

    Important: Do not wash the clutch inner friction plates in cleaning solvent.

  99. Separate the clutch plates for inspection.
  100. Remove and discard the shim or shims.

  101. Object Number: 164507  Size: SH
  102. Remove the oil restrictor from the rear output shaft, if replacing the shaft.

  103. Object Number: 165429  Size: SH
  104. Inspect the bearing in the clutch housing for being faulty. Refer to Transfer Case Cleaning and Inspection .
  105. If the bearing is faulty, use a brass drift and a hammer to remove the bearing.

  106. Object Number: 701623  Size: SH
  107. Remove both of the clutch lever pivot pins with the aluminum washers and the O-ring seals.

  108. Object Number: 701627  Size: SH
  109. Remove the clutch lever assembly from the control actuator lever.

  110. Object Number: 165035  Size: SH
  111. Remove the shift fork shaft.

  112. Object Number: 712346  Size: SH
  113. Remove the range shift fork and the range shift sleeve as an assembly.
  114. It may be necessary to lightly pry the roller on the shift fork from the control actuator lever.


    Object Number: 801284  Size: SH
  115. Remove the range shift sleeve from the range shift fork.

  116. Object Number: 164463  Size: SH
  117. Remove the input gear bearing outer retaining ring.

  118. Object Number: 712161  Size: SH

    Important: Depending on the version of the transfer case, it may have either a 3 pinion gear or 6 pinion gear planetary carrier assembly. The 3 pinion gear planetary carrier is used with transmission RPO M30 and the input gear splines are 27 teeth. The 6 pinion gear planetary carrier is used with transmission RPO MT1 and MN8 and the input gear splines are 32 teeth. The repair procedures are the same for both planetary carriers.

  119. Remove the high/low planetary carrier.

  120. Object Number: 165318  Size: SH
  121. Remove the planetary gear shaft retaining ring.

  122. Object Number: 165308  Size: SH
  123. Remove the planetary carrier lock ring.

  124. Object Number: 857313  Size: SH
  125. Remove the input gear front thrust washer.

  126. Object Number: 165294  Size: SH
  127. Remove the input gear from the planetary carrier.

  128. Object Number: 857314  Size: SH
  129. Remove the input gear rear thrust washer.

  130. Object Number: 165322  Size: SH
  131. Inspect the pilot bearing in the input gear for being faulty. Refer to Transfer Case Cleaning and Inspection .
  132. Remove the pilot bearing from the input gear using a brass drift and a hammer.

  133. Object Number: 895080  Size: SH
  134. Remove the inner retaining ring for the front output shaft bearing.

  135. Object Number: 895089  Size: SH
  136. Using a soft-face hammer, remove the front output shaft, with the bearing, from the front case half.

  137. Object Number: 895092  Size: SH
  138. Using a suitable punch, remove the front output shaft seal from the front case half.

  139. Object Number: 895094  Size: SH
  140. Remove the outer retaining ring for the front output shaft bearing.

  141. Object Number: 895096  Size: SH
  142. Inspect the front output shaft bearing for being faulty. Refer to Transfer Case Cleaning and Inspection .
  143. Remove the bearing from the front output shaft. Do not use the bearing again after removal.

  144. Object Number: 801286  Size: SH
  145. If damaged, remove the speed sensor reluctor wheel from the front output shaft, using a hydraulic press. Do not use the speed sensor reluctor wheel again after removal.

  146. Object Number: 165060  Size: SH
  147. If the cup plug in the front output shaft is leaking, remove the plug using a brass drift.

  148. Object Number: 712116  Size: SH
  149. Remove the input bearing retaining ring.

  150. Object Number: 712123  Size: SH
  151. Remove the input bearing.

  152. Object Number: 801288  Size: SH
  153. Inspect the front output shaft rear bearing for being faulty. Refer to Transfer Case Cleaning and Inspection .
  154. If the bearing is faulty, remove the bearing using the J 23907  (2) and the J 26941  (1).

  155. Object Number: 857315  Size: SH
  156. Remove the control actuator lever shaft retaining ring.

  157. Object Number: 857316  Size: SH
  158. Remove the control actuator lever shaft.
  159. Inspect the control actuator lever bearing and seal for being faulty. Refer to Transfer Case Cleaning and Inspection .
  160. If the bearing is leaking or faulty, remove the bearing from the case.