Drive Axle (Front) - Will Not Disengage

9215chevy02

Number: 91-476-4C

Section: 4C

Date: JAN. 1992

Corporate Bulletin No.: 167402

ASE No.: A3


Subject: FRONT AXLE WILL NOT DISENGAGE


Model and Year: 1983-1991 T TRUCKS


Owners of some 1983-1991 T vehicles may comment about inappropriate front axle disengagement. This condition may be due to a corroded transfer case vacuum actuator switch. To correct this condition a revised switch (P/N 15664811), constructed of noncorrosive stainless steel, should be installed.

SERVICE PROCEDURE:





The vacuum switch is located on the left upper side of the transfer case (Figure 1).

1. Raise the vehicle and support with suitable safety stands.

2. Remove the vacuum lines from the switch.

3. Remove the corroded switch from the transfer case.

4. Install a revised switch (P/N 15664811), coat the threads with thread sealant.

5. Connect the vacuum lines.

6. Lower the vehicle.

7. Check for oil leaks at the threads and vacuum leaks around the vacuum lines.

SERVICE PARTS INFORMATION

Part Number Description

15664811 Vacuum Actuator Switch

Parts are currently available from GMSPO.

WARRANTY INFORMATION

For vehicles repaired under warranty use:

Labor Operation: K4120

Use applicable labor time guide for labor hours.