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 cam worn

  1. Inspect for excessive wear on the shift cam, not allowing full shift fork travel. Refer to Transfer Case Cleaning and Inspection .
  2. Replace the faulty shift cam. Refer to Transfer Case Disassemble and Transfer Case Assemble .

High/low shift fork pads

  1. Inspect the shift fork pads for wear. Refer to Transfer Case Cleaning and Inspection .
  2. Replace the fork pads or other damaged components. Refer to Transfer Case Disassemble and Transfer Case Assemble .

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
  3. Replace the range sleeve if the teeth are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .
  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 .

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
  3. Replace the high/low planetary carrier if any of the above conditions are found. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Faulty high/low range fork

  1. Inspect the high/low range fork for damage or wear. Refer to Transfer Case Cleaning and Inspection .
  2. Replace the high/low range fork if it is faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Lockup shift collar assembly

  1. Inspect the lockup shift collar assembly for the following conditions:
  2. • Worn or damaged sleeve
    • Lock up collar teeth worn or damaged
  3. Replace the lockup shift collar assembly if it is faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .

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
  3. Replace the planetary differential if any of the above conditions are found. Refer to Transfer Case Disassemble and Transfer Case Assemble .

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 .
  2. Replace the bearing and the mainshaft if they are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Sun gears

  1. Inspect the sun gears for broken or damaged teeth. Refer to Transfer Case Cleaning and Inspection .
  2. Replace the sun gears if they are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .