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 in Transfer Case - Isuzu T150 Unit Repair.
  2. Replace the shift fork if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

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
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.
  3. Replace the range sleeve if the teeth are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.
  4. Replace the input shaft if the input shaft engagement teeth are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

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 in Transfer Case - Isuzu T150 Unit Repair.

  4. Replace the high/low range shift fork assembly if the spring or block are faulty. Refer to Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

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
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 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 - Isuzu T150 Unit Repair.

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 in Transfer Case - Isuzu T150 Unit Repair.

Shift shaft detents

  1. Inspect the shift detent springs for being faulty. Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.
  2. Inspect the detents on the shift shafts for excessive wear. Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.
  3. Replace the detent spring if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.
  4. Replace the shift shaft if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.