GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

DEFINITION: While shifting from HI range to LO range, there is gear clashing or the gear range cannot be selected.

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

High/low shift fork spring assembly

  1. Inspect the high/low shift fork spring assembly for the following conditions:
  2. • Worn high/low shift fork pin
    • Worn cam
    • Broken spring
  3. Replace the following components if found faulty:
  4. • The high/low shift fork spring assembly
    • The high/low shift fork pin

High/low shift fork

  1. Inspect the high/low shift fork for the following conditions:
  2. • Worn shift fork pads
    • Cracked or bent shift fork
  3. Replace the following components if found faulty:
  4. • The shift fork pads
    • The shift fork

High/low clutch

  1. Inspect the high/low clutch for the following conditions:
  2. • Engagement teeth for burrs or damage
    • Sliding freely on the rear output shaft
    • The high/low clutch collar for excessive wear
  3. Replace the high/low clutch if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Input shaft pilot bearing assembly

  1. Inspect for the following conditions:
  2. • Failed bearing in the input shaft
    • Journal on the rear output shaft for excessive wear or damage
  3. Replace the bearing if faulty. Refer to Input Shaft Pilot Bearing Replacement .
  4. Replace the rear output shaft if damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble .

High/low planetary carrier assembly

  1. Inspect the high/low planetary engagement teeth for burrs or damage. Refer to High/Low Planetary Carrier Cleaning and Inspection .
  2. Replace the high/low planetary carrier assembly if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .