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.

Faulty high/low range shift fork

  1. Inspect the high/low range shift fork for being damaged. Refer to Transfer Case Cleaning and Inspection.
  2. Replace the shift fork, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble.

Faulty engagement teeth on the range sleeve

  1. Inspect for the following conditions:
  2. • The input shaft 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 input shaft if the input shaft engagement teeth are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble.

High/low range shift fork block and spring

  1. Inspect the high/low range shift fork spring for being faulty.
  2. Inspect the shift block for wear.
  3. Refer to Transfer Case Cleaning and Inspection.

  4. Replace the high/low range shift fork assembly if the spring or block are faulty. Refer to Transfer Case Assemble.

High/low planetary carrier

  1. Inspect the high/low planetary carrier for the following conditions:
  2. • Planetary carrier low gear engagement teeth worn or damaged
    • Cracked carrier housing
    • Pinion gear 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.

2/4 wheel drive synchronizer

  1. Inspect the 2/4 wheel drive synchronizer sleeve for worn engagement teeth.
  2. Replace the synchronizer, if faulty. Refer to Transfer Case Assemble.

Shift shaft detents

  1. Inspect the shift detent springs for being faulty. Refer to Transfer Case Cleaning and Inspection.
  2. Inspect the detents on the shift shafts for excessive wear. Refer to Transfer Case Cleaning and Inspection.
  3. Replace the detent spring, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble.
  4. Replace the shift shaft, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble.