GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Avalanche - 4WD 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Transfer Case Will Not Shift

Cause

Correction

DEFINITION: While shifting from 4HI range to 4LO Lock range, there is gear clashing, no 4HI range, or the transfer case will not shift to 4LO Lock.

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

Shift detent lever
    • Inspect for the following conditions:
      • The shift detent lever at the shift fork cams for being worn
      • The shift detent lever torsion spring for being faulty
      • Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
    • Replace the following components if found faulty:
      • The shift detent lever cam
      • The shift detent lever spring
      • Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

High/low range shift fork
  1. Inspect the high/low shift fork for the following conditions:
    2. • Worn shift fork pads
    • The roller on the shift fork for wear or damage
    • Cracked or bent shift fork
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the following components if found faulty:
    3. • The shift fork pads
    • The shift fork
    • Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

Range sleeve

  1. Inspect the range sleeve for the following conditions:
    2. • Engagement teeth for burrs or damage
    • Sliding freely on the mainshaft
    • The range sleeve shift fork collar for excessive wear
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the range sleeve if 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 engagement teeth for burrs or damage. Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the high/low planetary carrier if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

Mainshaft front support bearing
  1. Inspect for the following conditions:
    2. • Failed front mainshaft support bearing in the input gear
    • Journal on the mainshaft for excessive wear or damage
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the bearing if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.
  3. Replace the mainshaft if damaged. 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. • Shift assembly hub for binding
    • Shift assembly sleeve for damage
    • Burred or damaged engagement teeth
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the shift assembly if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.

Drive sprocket
  1. Inspect for the following conditions:
    2. • Engagement teeth on the drive sprocket for burrs or damage
    • Worn bushing in the drive sprocket
    • Journal on the mainshaft for excessive wear or damage
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4482-NR4 Unit Repair.
  2. Replace the drive gear if damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.
  3. Replace the mainshaft if damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4482-NR4 Unit Repair.