GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 3289-20 Holding Fixture
    • J 5590 Pinion Bearing Race Installer - Rear
    • J 8092 Universal Driver Handle
    • J 36370 Drive Sprocket Needle Bearing Installer
    • J 37668-A Output Shaft Seal Installer
    • J 42738 Seal Installer
    • J 43484 Front Output Shaft Seal Installer
    • J 45380 Transfer Case Rear Bushing Remover and Installer
    • J 45540 Tone Ring and Bearing Installer
    • J 45549 Mainshaft Support Bearing Installer
    • J 45759 Assembly Fixture

    Object Number: 165657  Size: SH

    Important: 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 mounting studs to 29.5-30.5 mm (1.16-1.20 in) in height.

  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: 805660  Size: SH

    Important: When installing the input bearing, ensure the printing on the bearing is facing toward the front of the input gear.

  6. Using a press, install the input bearing. Ensure the bearing is supported by the internal race.

  7. Object Number: 729520  Size: SH
  8. Install the input gear bearing retaining ring.

  9. Object Number: 729518  Size: SH
  10. Install the input gear.

  11. Object Number: 729426  Size: SH
  12. Install the input gear retaining ring.

  13. Object Number: 164524  Size: SH
  14. Install the front output shaft bearing in the front case.
  15. • The bearing will slide in if it is installed straight.
    • The cage side of the bearing faces the inside of the case.

    Object Number: 164528  Size: SH
  16. Install a new retaining ring for the front input shaft bearing.

  17. Object Number: 724388  Size: SH
  18. Install the front output shaft.

  19. Object Number: 805641  Size: SH
  20. Install the front output shaft retaining ring.

  21. Object Number: 729424  Size: SH
  22. Install the viscous coupling.

  23. Object Number: 729528  Size: SH
  24. Install the mainshaft assembly.

  25. Object Number: 729532  Size: SH

    Important: The blue colored link faces up or toward the rear of the case.

  26. Install the drive chain and sprockets.

  27. Object Number: 729562  Size: SH
  28. Install the driven sprocket retaining ring.

  29. Object Number: 729534  Size: SH
  30. Install the carrier retaining ring.

  31. Object Number: 805662  Size: SH
  32. Lubricate the planetary carrier sun gear bearing with transfer case fluid.
  33. Install the sun gear bearing.

  34. Object Number: 729533  Size: SH

    Important: Ensure the spline engages with both the sprocket and viscous coupling cover. The sun gear shoulder will bottom on the sprocket if it is installed correctly.

  35. Install the sun gear.

  36. Object Number: 729418  Size: SH
  37. Install the sun gear thrust washer.

  38. Object Number: 729555  Size: SH

    Important: When installing the carrier assembly, a snap should be felt and heard when the carrier is properly seated.

  39. Install the carrier assembly.

  40. Object Number: 805663  Size: SH
  41. Using the J 8092  (1) and the J 45549  (2), install the mainshaft rear bearing in the rear output shaft.

  42. Object Number: 729556  Size: SH
  43. Install the rear output shaft in the annulus gear.

  44. Object Number: 729557  Size: SH

    Caution: The vehicle could roll while in park if the annulus gear becomes disengaged from the rear output shaft. Always install a new rear output shaft to annulus gear retaining ring. Ensure the rear output shaft retaining ring is fully seated in the annulus gear.

    Notice: Damage may occur to the viscous coupling if the retaining ring for the rear output shaft to the annulus gear fails or becomes dislodged during vehicle operation. Always install a new rear output shaft to annulus gear retaining ring. Ensure the rear output shaft retaining ring is fully seated in the annulus gear.

  45. Install the annulus gear retaining ring.

  46. Object Number: 729402  Size: SH
  47. Install the oil pump assembly.

  48. Object Number: 729400  Size: SH
  49. Install the speed reluctor wheel retaining ring.

  50. Object Number: 730254  Size: SH

    Important: 

       • Always use a NEW speed reluctor wheel.
       • The speed reluctor wheel should just contact the retaining ring.

  51. Using a press, the J 45540  (2) and the J 5590  (1), install the speed reluctor wheel until it is just contacting the retaining ring.

  52. Object Number: 729559  Size: SH

    Important: Ensure the retaining ring groove on the rear output shaft bearing is facing toward the rear of the rear output shaft.

  53. Using a press, the J 45540  (2) and the J 5590  (1), install the rear output shaft bearing.

  54. Object Number: 729561  Size: SH
  55. Install the rear output shaft bearing retaining ring.

  56. Object Number: 729398  Size: SH
  57. Install the rear output shaft assembly.

  58. Object Number: 801306  Size: SH
  59. Using the J 8092  (1) and the J 36370  (2), install the front output shaft rear bearing.

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

  62. Object Number: 1868938  Size: SH

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

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

  64. Object Number: 729396  Size: SH

    Important: Ensure the O-ring is in place in the oil pump.

  65. Install the oil pump tube O-ring in the oil pump.
  66. Install the oil pump screen and the oil pump tube.
  67. Install the chip collector magnet.
  68. 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.

  69. Apply a 3 mm (1/8 in) bead of RTV sealant GM P/N 12345739 (Canadian P/N 10953472) or equivalent to the front case half.
  70. Install the locating pins in the front case half.

  71. Object Number: 649760  Size: SH
  72. Align the rear case on the rear output shaft bearing.
  73. Install the rear case half.
  74. Open the outer rear output shaft bearing retaining ring.
  75. Important: Ensure the rear output shaft bearing retaining ring is seated in the groove properly by prying up on the shaft on the rear output shaft assembly.

  76. Lower the rear case on to the rear output shaft bearing.
  77. Remove the snap ring pliers.
  78. Important: Ensure the rear case is squarely seated on the alignment dowels when it is installed.

  79. Lower the rear case on to the alignment dowels.

  80. Object Number: 740281  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. New nylon coated case bolts and aluminum washers must be used. 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.

  81. Position the brackets to the proper bolt hole.
  82. Notice: Refer to Fastener Notice in the Preface section.

  83. Install NEW case half bolts and washers.
  84. Tighten
    Tighten the case half bolts to 37 N·m (27 lb ft).


    Object Number: 801307  Size: SH
  85. Using the J 45380 , install a new rear output shaft bushing.
  86. 47.1. Install the bushing on the finger section of the J 45380 .
    47.2. Install the finger section to the main body of the J 45380 .
    47.3. Position the bushing and tool to the case.
    47.4. Using a hammer and the J 45380 , install the bushing.

    Object Number: 678288  Size: SH
  87. Using the J 42738 , install the input seal.

  88. 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.

  89. Using the J 37668-A , install the rear output shaft seal.

  90. Object Number: 678236  Size: SH
  91. Using the J 43484  (2) and the J 8092  (1), install the front output shaft seal.

  92. Object Number: 662047  Size: SH
  93. Install the transfer case speed sensor.
  94. Tighten
    Tighten the transfer case speed sensor to 15 N·m (11 lb ft).


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

  97. Object Number: 660282  Size: SH

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

  98. Install the drain plug.
  99. Tighten
    Tighten the drain plug to 20 N·m (15 lb ft).


    Object Number: 660281  Size: SH
  100. Install the fill plug.
  101. Tighten
    Tighten the fill plug to 20 N·m (15 lb ft).


    Object Number: 724554  Size: SH
  102. Install the access plug.