Transfer Case - Vibration/Noise While Driving

File in Section: 7 - Transmission

Bulletin No.: 86-74-05

Date: October, 1998

Subject:
Leak from Transfer Case Rear Extension, Vibration/Noise while Driving (Replace Transfer Case Rear Extension)

Models:
1998 Chevrolet and GMC L Van Models
Equipped with All Wheel Drive Transfer Case (RPO NP3)

Condition

Some owners may comment about a driveline leak or a vibration/noise when the vehicle is driven. The leak may be centered around the transfer case rear extension oil seal.

Cause

Conditions may be caused from an oversized bushing bore in the transfer case rear extension. This may allow the bushing to "walk" out of the extension. If this bushing moves, the bushing may cut or damage the rear extension seal and cause a fluid leak.

Correction

Inspect the rear extension bushing for signs of looseness. Verify that the bushing has not moved inside of the extension. If the bushing is loose or has moved, replace the rear extension. Also inspect the seal. If the seal shows signs of damage, replace the seal. Refer to the 1998 Unit Repair Manual, Volume 2, Section 4, Borg Warner 4472 for extension replacement procedures. Use the part numbers listed below.

Parts Information

P/N Description Qty

12545732 Extension, Transfer 1
Case Rear

10117848 Seal, Transfer Case 1

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation Description Labor Time

K4260 Gasket or Seal, Use published
Transfer Case labor operation
Rear Output Shaft time
Housing - Replace