GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • DT-48021 Seal Installer
    • DT-48022 Output Bushing Installer
    • J 3289-20 Holding Fixture
    • J 8092 Universal Handle
    • J 36370 Drive Sprocket Needle Bearing Installer
    • J 37668-A Seal Installer
    • J 42738 Seal Installer
    • J 43484 Seal Installer
    • J 45380 Transfer Case Rear Bushing Remover and Installer
    • J 45383 Input Gear Pilot Bearing Installer
    • J 45759 Assembly Fixture

    Object Number: 165657  Size: SH

    Important: 

       • Because of manufacturing design changes, the transfer case was manufactured with either 1st design components or 2nd design components. When assembling the transfer case, follow the procedure for that design level. The changes are for manufacturing purposes only and do not enhance the performance of the transfer case. The following are the 2nd design components:
          - The oil pump suction pipe is nylon and the oil pump screen is serviced only with the pipe.
          - The 2/4 wheel drive synchronizer gear and drive sprocket sleeve are net formed as 1 piece.
       • The following service procedure covers light duty (LD), heavy duty (HD) and super heavy duty (SHD) versions of this transfer case.
            When installing the new retaining rings in any of the following service procedures, ensure that the retaining rings are properly seated before proceeding to the next service procedure. Always use NEW retaining rings.

  1. Install the adapter studs to 29.5-30.5 mm (1.16-1.20 in) in height, if removed.

  2. Object Number: 819573  Size: SH
  3. Attach the J 45759 to the front transfer case using the adapter studs. All of the assembly procedures can be performed with the case mounted to the J 45759 .
  4. Install the J 45759  (2) into the J 3289-20  (1) and secure with the pivot pin.

  5. Object Number: 801306  Size: SH
  6. Using the J 8092  (1) and the J 36370  (2), install the front output shaft rear bearing.
  7. • The letters on the bearing face toward the tool.
    • Use the double shoulder side of the J 36370 .
    • The install depth from the case shoulder is 1.4-1.6 mm (0.055-0.063 in).

    Object Number: 1868934  Size: SH
  8. SHD only - Install a new rear output shaft bushing, using the J 8092  (1) and DT-48022  (2).
  9. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 393375  Size: SH
  10. Install the control lever shaft support and seal.
  11. Tighten
    Tighten the control lever shaft support to 34 N·m (25 lb ft).


    Object Number: 393275  Size: SH
  12. Install the shift detent lever shaft.

  13. Object Number: 393324  Size: SH
  14. For the non-super heavy duty model, install the input gear bearing. The cage on the bearing faces forward.
  15. For the non-SHD model, install the input gear bearing inner retaining ring.
  16. For the SHD model, install the retaining ring for the input gear bearing.
  17. Important: When installing the input gear bearing, ensure that the groove in the input gear bearing is facing up.

  18. For the SHD model, expand the retaining ring and install the input gear bearing with the groove up.
  19. For the SHD model, fully seat the retaining ring in the bearing groove.

  20. Object Number: 164524  Size: SH
  21. Install the front output shaft front bearing. The cage on the bearing faces forward.

  22. Object Number: 164528  Size: SH
  23. Install the front output shaft front bearing inner retaining ring.

  24. Object Number: 804160  Size: SH
  25. If it is a new shaft, or if the cup plug was removed, install the cup plug in the front output shaft, using a suitable driver.
  26. The installed depth of the cup plug is 26.75 mm (1.05 in) from the end of the shaft.


    Object Number: 724388  Size: SH
  27. Install the front output shaft assembly.

  28. Object Number: 717108  Size: SH
  29. Install the front output shaft front bearing outer retaining ring.

  30. Object Number: 165286  Size: SH
  31. Install the planetary carrier thrust washer. The thrust washer with the tabs must be installed.

  32. Object Number: 801303  Size: SH
  33. Install the needle bearing in the input gear, using the J 8092  (1) and the J 45383  (2). Use the large diameter of the tool to install the bearing.

  34. Object Number: 165294  Size: SH
  35. Install the input gear in the planetary carrier.
  36. Ensure the input gear turns freely. If the input gear does not turn freely, inspect for debris.

  37. Object Number: 165300  Size: SH
  38. Install the planetary carrier front thrust washer. The thrust washer without the tabs must be installed.

  39. Object Number: 165308  Size: SH

    Important: If the lock plate has a stamped letter "E", ensure that the letter "E" stamped on the lock plate is facing up.

  40. Install the planetary carrier lock plate.

  41. Object Number: 165318  Size: SH
  42. Install the retaining ring for the input gear.

  43. Object Number: 165341  Size: SH
  44. Install the high/low planetary carrier.

  45. Object Number: 164463  Size: SH
  46. Install the outer retaining ring for the input gear bearing.

  47. Object Number: 393235  Size: SH
  48. Install the high/low shift fork on the high/low range sleeve.
  49. Install the high/low range sleeve with the shift fork to the planetary carrier.
  50. Position the shift fork pin in the shift detent lever slot.

  51. Object Number: 392293  Size: SH
  52. If 1st design, mount the rear output shaft in a soft-jaw vise with the input end up.
  53. If 1st design, install the drive sprocket sleeve on the rear output shaft.
  54. If 1st design, install the drive sprocket front retaining ring.

  55. Object Number: 1492329  Size: SH
  56. If 2nd design, mount the rear output shaft in a soft-jaw vise with the input end up.
  57. If 2nd design, install the 2/4 wheel drive synchronizer gear on the rear output shaft.

  58. Object Number: 812463  Size: SH
  59. If disassembled, assemble the synchronizer assembly.
  60. 35.1. Install the inserts (7) in the hub (6).
    35.2. Install the insert springs (5 and 8).
       • Ensure the hooked end of the spring is located in an insert slot.
       • The hooked ends are opposite each other and not installed in the same insert.
    35.3. Install the synchronizer sleeve (4) on the synchronizer hub (6). The sleeve with the taper and groove end aligns to the shorter side teeth of the hub.

    Ensure the inserts (7) are aligned with the splines in the synchronizer sleeve (4).


    Object Number: 812459  Size: SH
  61. If 1st design, install the synchronizer rings on the rear output shaft. Align the tabs of the outer ring with the slots in the inner ring.
  62. 36.1. Install the inner ring.
    36.2. Install the middle ring.
    36.3. Install the outer ring.
  63. If 1st design, install the synchronizer assembly.
  64. • The taper or groove end of the synchronizer sleeve faces toward the input end of the rear output shaft.
    • The outer synchronizer ring tabs align to the synchronizer hub.

    Object Number: 1492326  Size: SH
  65. If 2nd design, install the synchronizer rings on the rear output shaft. Align the tabs of the outer ring with the slots in the inner ring.
  66. 38.1. Install the inner ring.
    38.2. Install the middle ring.
    38.3. Install the outer ring.
  67. If 2nd design, install the synchronizer assembly.
  68. • The taper or groove end of the synchronizer sleeve faces toward the input end of the rear output shaft.
    • The outer synchronizer ring tabs align to the synchronizer hub.

    Object Number: 812457  Size: SH
  69. Install the synchronizer retaining ring. Ensure the retaining ring is fully seated in the groove.

  70. Object Number: 391145  Size: SH
  71. Install the 2/4 wheel drive mode shift fork on the synchronizer assembly.
  72. Install the shift shaft in the mode shift fork.

  73. Object Number: 391112  Size: SH

    Important: Ensure the mode shift fork is installed with the roller side down.

  74. Install the shift shaft and the synchronizer assembly with the rear output shaft in the front case half and the high/low range sleeve.

  75. Object Number: 812456  Size: SH
  76. If 1st design, install the 2/4 wheel drive synchronizer gear.
  77. • Ensure to align the middle synchronizer tabs to the gear.
    • Ensure the gear is aligned to the synchronizer sleeve.

    Object Number: 163905  Size: SH

    Important: When performing the following service procedure, ensure that marks that were used to mark the position of the chain to the relationship of the chain to the sprockets.

  78. Install the drive chain on the front output shaft and the rear output shaft assembly.

  79. Object Number: 701617  Size: SH
  80. Install the drive sprocket retaining ring.

  81. Object Number: 701619  Size: SH
  82. Install the driven sprocket retaining ring.

  83. Object Number: 701595  Size: SH
  84. Install the oil pump on the rear output shaft.

  85. Object Number: 163888  Size: SH
  86. Install a new oil pump O-ring for the oil pump suction pipe in the oil pump.

  87. Object Number: 701592  Size: SH

    Important: Install the speed reluctor wheel with the step toward the oil pump assembly.

  88. Install the speed reluctor wheel.

  89. Object Number: 701589  Size: SH

    Important: When installing the rear output shaft bearing on the rear output shaft, ensure the groove on the rear output shaft bearing is facing up.

  90. Install the rear output shaft bearing.

  91. Object Number: 701586  Size: SH
  92. Install a NEW rear output shaft bearing retaining ring.

  93. Object Number: 164548  Size: SH
  94. Install a new O-ring seal on the shift detent spring bolt.
  95. Install the shift detent spring, the plunger, and the bolt.
  96. Tighten
    Tighten the shift detent bolt to 17 N·m (13 lb ft).


    Object Number: 163872  Size: SH
  97. If 1st design, install the oil pump screen in the front case half.
  98. 55.1. Install the connector on the oil pump screen
    55.2. Install the oil pump suction pipe in the connector.
    55.3. Install the oil pump suction pipe in the oil pump body.

    Object Number: 1348893  Size: SH
  99. If 2nd design, install the oil pump suction pipe assembly.
  100. 56.1. Install the screen in the case.
    56.2. Install the suction pipe to the oil pump.
    56.3. Inspect for the O-ring not being damaged and in the proper position.

    Object Number: 163856  Size: SH
  101. Install the magnet.

  102. Object Number: 391094  Size: SH
  103. Install the shift fork shaft spring on the shift shaft.

  104. Object Number: 724251  Size: SH
  105. Remove the 1st design oil pump wear sleeve from the rear case half.

  106. Object Number: 1868938  Size: SH

    Important: Ensure the oil pump wear sleeve is properly positioned to the largest lug of the oil pump.

  107. Install the 2nd design oil pump wear sleeve (1) to the oil pump (2).

  108. Object Number: 163815  Size: SH

    Important: Ensure the locating pins are installed in the front case half.

  109. Install the locating pins in the front case, if necessary.

  110. Object Number: 698077  Size: SH

    Notice: Apply the proper amount of sealant to the flange when assembling the transfer case. Excessive amounts of sealant can plug the oil pump screen, resulting in internal component failure.

    Important: Ensure both sealing surfaces of the front and rear case halves are free of dirt, oil, and cleaning solvent.

  111. Apply a 3 mm (1/8 in) bead of RTV sealant GM P/N 12345739 (Canadian P/N 10953541) or equivalent to the front case half.

  112. Object Number: 163737  Size: SH
  113. Align the outer retaining ring tabs for the rear output shaft bearing with the slot in the rear case half.
  114. Install the rear case half to the front case half.

  115. Object Number: 649760  Size: SH
  116. Using a pair of snap ring pliers, open the outer retaining ring for the rear output shaft bearing.
  117. Insert a rubber coated screwdriver into the speed sensor hole and lift up on the speed reluctor wheel, then seat the retaining ring.

  118. Object Number: 1248074  Size: SH

    Notice: This component is made of magnesium. Proper assembly is required to prevent damage. Ensure the magnesium transfer case housings are properly insulated from all external steel components, or galvanic corrosion will occur. Use only the transfer case bolts/studs with the cup style aluminum washer. Use only aluminum fill and drain plugs. Use only aluminum brackets under the case bolts. Ensure new seals are installed that have a rubber insulated outside diameter and have no tears or cuts. Extensive damage will occur if there is galvanic corrosion between the magnesium and steel components.

  119. Align the brackets to the proper bolt holes.
  120. Install the NEW case half bolts or studs and the aluminum washers.
  121. Tighten
    Tighten the case half bolts to 38 N·m (28 lb ft).


    Object Number: 801307  Size: SH

    Important: The J 45380 does not work on the SHD version of the transfer case.

  122. LD and HD only - Install a new rear output shaft bushing, using the J 45380 .
  123. 69.1. Install the bushing on the finger section of the J 45380 .
    69.2. Install the finger section to the main body of the J 45380 .
    69.3. Position the bushing and tool to the case.
    69.4. Using a hammer and the J 45380 , install the bushing.

    Object Number: 687288  Size: SH

    Important: When installing the rear output shaft seal, ensure that the drain hole is pointed down at an angle at which the transfer case would be installed in the vehicle.

  124. LD and HD only - Using the J 37668-A , install the rear output shaft seal to the transfer case.

  125. Object Number: 1868941  Size: SH

    Important: When installing the rear output shaft seal, ensure that the drain hole is pointed down at an angle at which the transfer case would be installed in the vehicle.

  126. SHD only - Using the J 8092  (1) and DT-48021  (2) , install the rear output shaft seal to the transfer case.

  127. Object Number: 678236  Size: SH
  128. Using the J 43484  (2) and the J 8092  (1), install the front output shaft seal in the transfer case.

  129. Object Number: 678288  Size: SH
  130. Using the J 42738 , install the input shaft seal to the transfer case.

  131. Object Number: 1248078  Size: SH
  132. Install a NEW O-ring seal on the vehicle speed sensor.
  133. Lubricate the vehicle speed sensor O-ring seal with transfer case fluid.
  134. Install the speed sensor in the transfer case.
  135. Tighten
    Tighten the speed sensor to 15 N·m (11 lb ft).


    Object Number: 1869823  Size: SH
  136. Apply a thin layer of retaining compound GM P/N 12377901, Canadian P/N 10953504, or equivalent, to the NEW aluminum vent pipe.
  137. Tap the NEW aluminum vent pipe into the case; ensure the vent pipe is aligned in the direction shown.

  138. Object Number: 393367  Size: SH
  139. Install the gear indicator switch with the gasket.
  140. Tighten
    Tighten the gear indicator switch to 27 N·m (20 lb ft).


    Object Number: 393265  Size: SH
  141. Install the shift control lever and foam seal.
  142. Install the shift control lever retaining bolt.
  143. Tighten
    Tighten the shift control lever retaining bolt to 27 N·m (20 lb ft).


    Object Number: 1248071  Size: SH

    Important: Ensure that the correct access hole plug is used for the SHD models.

  144. Install the access hole plug in the transfer case.

  145. Object Number: 1248076  Size: SH

    Important: Use only drain and fill plugs made of aluminum. Steel or brass plugs are not compatible with the magnesium case.

  146. Install the drain plug (2).
  147. Tighten
    Tighten the drain plug to 20 N·m (15 lb ft).

  148. Install the fill plug (1).
  149. Tighten
    Tighten the fill plug to 20 N·m (15 lb ft).