4WD Transfer Inoperative (Replace Actuator/Shift Detent Plunger)

Some owners may comment that the 4WD is inoperative.

This condition may be caused by an inoperative transfer case motor (actuator).

A new transfer case Teflon®-coated shift detent plunger (poppet) has been developed in order to correct this condition. This coating on the exterior surface of the poppet should reduce shift effort and wear. If you determine that the transfer case actuator is inoperative, replace the actuator and the poppet. Use the following procedure and the part numbers listed below.

1. Remove the transfer case actuator.
2. Install a new transfer case actuator, P/N 12474401.
3. Remove the transfer case oil drain plug. Drain the oil from the transfer case. Refer to the Transfer Case subsection in the appropriate Service Manual.
4. Remove the plunger (poppet) screw. The poppet and the spring should come out with the screw.

Notice: Do not overtighten the poppet screw. Overtightening may damage the screw.

Important: Verify that the O-ring on the screw is not damaged. Replace a damaged O-ring.

5. Install the new coated poppet, P/N 12474072 (blue), the spring, and the screw.

Tighten
Tighten the screw to 14-20 N·m (10-15 lb ft).

6. Install the transfer case oil drain plug.

Tighten
Tighten the drain plug to 16-24 N·m (12-18 lb ft).

Important: Do not use standard DEXRON®III. Performance of the transfer case may be impaired.

7. Remove the transfer case oil fill plug. Fill the transfer case with 2 qts (1.9L) of Automatic (Auto Trac) transfer case fluid, P/N 12378396.
8. Install the transfer case oil fill plug.

Tighten
Tighten the fill plug to 16-24 N·m (12-18 lb ft).

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: