TRANSFER CASE DIAGNOSTIC AND EXCHANGE PROCEDURE

VEHICLES AFFECTED: 1989-90 K3 TRUCKS EQUIPPED WITH BORG-WARNER 1370 OR 4470 TRANSFER CASE

*THIS BULLETIN CANCELS AND REPLACES BULLETIN NUMBER 867401R TO INCLUDE THE 4470 TRANSFER CASE.

THIS BULLETIN COVERS:

*Preliminary diagnosis and exchange procedure for the 1370 and 4470 Transfer Cases.

*In order to give needed product feedback ANY 1370 or 4470 Transfer Case needing warranty repair will be exchanged for a replacement unit.

IMPORTANT: Customer pay units requiring repair can continue to be serviced using individual parts available through CANSPO.

SERVICE INFORMATION

* Preliminary Diagnosis Procedure:

- Insusre that the clutch coil relay (mounted to the cowl, under the hood) is present and properly mounted. Refer to Section 7D of Service Manual X-9031.

- Refer to Service Manual X-9031 Diagnostic Charts.

- Insure correct oil fill.

- Insure the transfer case shift linkage is properly adjusted.

- Insure the shift linkage is free and not blocked by the wiring cable.

- Insure all wiring connections are making good contact and are properly seated.

- Insure all engine and transmission mounts are tight.

- Check for proper tire inflation.

EXCHANGE PROCEDURE:

1. Reference Figures No. 1, 2 and 3, and have information available before calling. If the vehicle has an oil leak, determine where the leak is by using the oil leak identification chart. The noise and shifting charts can be filled out by using check marks. It is necessary to record this information as it will be needed to fill out the form on the transfer case being returned. (Blank forms will be shipped with exchange unit.) Record the GM part number, the Borg-Warner part number, and the unit serial number from the I.D. tag located at the rear of the transfer case.

2. Call Technical Assistance. TAC will arrange with Borg-Warner Automotive to ship an exchange unit within one working day (24 hours.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.