GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 2619-01 Slide Hammer
    • J 3289-20 Holding Fixture
    • J 22912-B Split Plate Bearing Puller
    • J 23907 Slide Hammer with Bearing Adapter
    • J 26941 Bushing and Bearing Remover - 3-4 inch
    • J 45358 Case Spreader
    • J 45548 Mainshaft Support Bushing/Bearing Remover
    • J 45759 Assembly Fixture

    Object Number: 824069  Size: SH
  1. Using the adapter studs, attach the J 45759 to the transfer case. 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 work bench.
  4. Install the J 45759  (2) into J 3289-20  (1) and secure with pivot pin.

  5. Object Number: 819569  Size: SH
  6. Remove the drain plug and the fill plug. Ensure all of the transfer case fluid is drained out of the transfer case.
  7. Notice: Refer to Transfer Case Seal Removal Notice in the Preface section.


    Object Number: 819585  Size: SH

    Important: The front output shaft seal is a two piece internal seal. The inner seal race is a force fit on the front output shaft.

  8. Remove the front output shaft seal by inserting a flat-tipped screwdriver behind the inner race of the seal.
  9. Pry the inner seal race forward.

  10. Object Number: 819650  Size: SH
  11. Using a small pry bar, move the inner seal race forward on the front output shaft.
  12. Remove the inner seal race from the front output shaft.

  13. Object Number: 819658  Size: SH
  14. Insert a flat-tipped screwdriver or a small pry bar between the outer lip of the front output shaft seal and the transfer case.
  15. Remove the remaining part of the front output shaft seal from the transfer case.

  16. Object Number: 819575  Size: SH
  17. Remove the encoder motor bracket bolt.
  18. Remove the encoder motor mounting bolts.
  19. Remove the encoder motor assembly.

  20. Object Number: 819577  Size: SH
  21. Remove the vehicle speed sensor (VSS) and the O-ring seal.
  22. Notice: Refer to Transfer Case Seal Removal Notice in the Preface section.


    Object Number: 819580  Size: SH
  23. Remove the rear output shaft seal by prying it out with a flat-blade screwdriver.
  24. Remove the shipping seal from the rear output shaft, if equipped.

  25. Object Number: 819583  Size: SH
  26. Remove the transfer case retaining bolts and washers.
  27. Mark the location of the brackets.

    Notice: Refer to Machined Surface Damage Notice in the Preface section.


    Object Number: 819584  Size: SH
  28. Using the J 45358 between the tabs on the case halves, shear the sealer that is holding the case halves together.
  29. Using pry bars at each side of the case, remove the case from the locating pins.

  30. Object Number: 819587  Size: SH
  31. Remove the rear case half from the front case half. The rear output shaft will come with the rear case half.

  32. Object Number: 819589  Size: SH
  33. Remove the shift fork shaft spring.

  34. Object Number: 819648  Size: SH
  35. Remove the rear sun gear.

  36. Object Number: 819590  Size: SH
  37. Remove the rear output shaft thrust washer.

  38. Object Number: 819593  Size: SH
  39. Remove the planetary differential assembly.

  40. Object Number: 819595  Size: SH
  41. Remove the front sun gear.

  42. Object Number: 819597  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.

  43. Remove the chain with the drive sprocket and driven sprocket.

  44. Object Number: 1326259  Size: SH

    Important: There was a mid year production change in the design to the mainshaft and the drive sprocket. If the mainshaft or the drive sprocket is found faulty during inspection, it may require the replacement of both components. If the drive sprocket and the mainshaft are the older designs and either component requires replacement, both the mainshaft and drive sprocket must be replaced as a kit. The replacement components will only be the new design. If the mainshaft and the drive sprocket are the new design, the components can be replaced individually.

  45. Inspect the drive sprocket to identify if it is the older design (1) or the newer design (2).
  46. There is only a slight difference to the drive sprocket on the rear surface. If the rear of the sprocket is almost flat, it is the old design (1). If the rear of the sprocket has a slight step of approximately 1 mm (0.039 in), it is the new design (2).


    Object Number: 819600  Size: SH
  47. Remove the drive sprocket thrust washer.

  48. Object Number: 819601  Size: SH
  49. Remove the lockup shift assembly and lockup mode shift fork.

  50. Object Number: 819603  Size: SH
  51. Remove the lockup mode shift fork from the lockup shift assembly.

  52. Object Number: 819604  Size: SH
  53. If necessary, disassemble the lockup shift assembly.
  54. 31.1. Remove the retainer ring from the sleeve.
    31.2. Remove the hub.
    31.3. Remove the spring.

    Object Number: 819605  Size: SH
  55. Remove the inner lockup hub.

  56. Object Number: 819606  Size: SH
  57. Remove the magnet.

  58. Object Number: 819669  Size: SH
  59. Remove the oil pump assembly with the hose and screen.

  60. Object Number: 819607  Size: SH
  61. Disconnect the oil pump hose from the oil pump screen.
  62. Disconnect the oil pump hose from the oil pump.

  63. Object Number: 819608  Size: SH
  64. Remove the shift fork shaft.

  65. Object Number: 819610  Size: SH

    Notice: In order to prevent component damage, properly remove and install the shift detent lever shaft assembly. When removing or installing the shift detent lever shaft assembly, keep the shaft straight and do not tilt. Tilting the shift detent lever shaft assembly in the transfer case housing will break the tip on the end of the shaft.

  66. Remove the shift detent lever assembly.
  67. • Rotate the high/low shift fork roller from the shift detent lever assembly.
    • Lift straight up on the shift detent lever assembly.

    Object Number: 819611  Size: SH
  68. If necessary, disassemble the shift detent lever assembly.
  69. 39.1. Hold the shift detent lever assembly by one tab of the spring (3), in a vise.
    39.2. Rotate the other spring tab and slide the detent lever cam (1) off the shaft.
    39.3. Remove the sleeve (2).
    39.4. Push the shaft (4) out of the spring (3).

    Object Number: 819612  Size: SH
  70. Remove the mainshaft.

  71. Object Number: 849625  Size: SH
  72. Remove the high/low range sleeve with the high/low range shift fork.

  73. Object Number: 819614  Size: SH
  74. Remove the range shift fork from the range shift sleeve.

  75. Object Number: 849626  Size: SH
  76. Remove the input shaft thrust washer.

  77. Object Number: 849627  Size: SH
  78. Remove the high/low planetary carrier.

  79. Object Number: 849628  Size: SH
  80. Inspect the mainshaft front support bearing for being faulty. Refer to Transfer Case Cleaning and Inspection .
  81. Using a brass drift and a hammer, remove the mainshaft front support bearing from the planetary carrier assembly.

  82. Object Number: 819619  Size: SH
  83. Remove the front output shaft assembly.

  84. Object Number: 819620  Size: SH
  85. If the cup plug in the front output shaft is leaking, remove the plug using a brass drift.

  86. Object Number: 849322  Size: SH
  87. Using a hammer and a suitable punch, remove the input seal.

  88. Object Number: 819622  Size: SH
  89. Using a hammer and a brass drift, remove the input shaft bearing from the front case half.

  90. Object Number: 819623  Size: SH
  91. Using a brass drift, remove the front output shaft bearing from the front case half.

  92. Object Number: 819625  Size: SH
  93. Remove the retaining ring for the annulus gear.

  94. Object Number: 819628  Size: SH
  95. Remove the annulus gear from the front case half.

  96. Object Number: 819664  Size: SH
  97. If necessary, remove the vent from the front case half.

  98. Object Number: 819630  Size: SH
  99. Remove the rear output shaft from the rear case half.
  100. 55.1. Spread the rear output shaft rear bearing outer retaining ring.
    55.2. Using a soft-face hammer, tap on the end of the rear output shaft.

    Object Number: 819633  Size: SH
  101. Using a hydraulic press and the J 22912-B , remove the speed reluctor wheel.
  102. Do not use the speed reluctor wheel again.


    Object Number: 819634  Size: SH
  103. Remove the retaining ring for the rear output shaft bearing.

  104. Object Number: 819635  Size: SH
  105. Using a hydraulic press, remove the rear output shaft bearing.

  106. Object Number: 819654  Size: SH
  107. Inspect the mainshaft rear support bushing in the rear output shaft for being faulty. Refer to Transfer Case Cleaning and Inspection .
  108. Using the J 2619-01  (1) and the J 45548  (2), remove the mainshaft rear support bushing from the rear output shaft.

  109. Object Number: 819636  Size: SH
  110. Using the J 26941  (1) and the J 23907  (2), remove the rear bearing for the front output shaft from the rear case.

  111. Object Number: 819629  Size: SH
  112. Remove the seal for the shift detent lever shaft by prying it out from the case.