GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

DEFINITION: Loss of the transfer case drive torque during deceleration, acceleration, or under load.

Review the Symptoms - Transfer Case and perform the necessary inspections.

Shift detent cam worn

  1. Inspect for excessive wear on the shift detent cam, not allowing full shift fork travel. Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the faulty shift detent cam. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

High/low shift fork pads

  1. Inspect the shift fork pads for wear. Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the fork pads or other damaged components. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

Faulty high speed teeth on range sleeve

  1. Inspect for the following conditions:
  2. • The input gear high speed engagement teeth for wear or damage
    • The engagement teeth on the range sleeve for wear or damage
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  3. Replace the range sleeve if the teeth are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.
  4. Replace the high/low planetary carrier assembly if the input gear engagement teeth are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

High/low planetary carrier

  1. Inspect the high/low planetary carrier for the following conditions:
  2. • Low speed engagement teeth worn or damaged
    • Cracked carrier housing
    • Pinion gear bushings worn or out of position
    • Pinion gears broken or damaged teeth
    • Pinion gears seized
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  3. Replace the high/low planetary carrier if any of the above conditions are found. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

Faulty high/low range fork

  1. Inspect the high/low range fork for damage or wear. Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the high/low range fork if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

Lockup shift assembly

  1. Inspect the lockup shift assembly for the following conditions:
  2. • Worn or damaged sleeve
    • Lock up collar teeth worn or damaged
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  3. Replace the lockup shift assembly if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

Planetary differential

  1. Inspect the planetary differential for the following conditions:
  2. • Cracked carrier housing
    • Pinion gear bushings worn or out of position
    • Pinion gears broken or damaged teeth
    • Pinion gears seized
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  3. Replace the planetary differential if any of the above conditions are found. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

Mainshaft front support bearing

  1. Inspect the bearing in the input gear and the mainshaft journal for excessive wear. Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the bearing and the mainshaft if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

Sun gears

  1. Inspect the sun gears for broken or damaged teeth. Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the sun gears if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.