CAMPAIGN: REAR AXLE CONTROL MOTOR LUBE OMITTED

MODELS: 1991 C7 TRUCKS WITH HRU/HNG (GJ4 & HR 1)

NOTE: Oshawa will notify involved dealers via telephone on Monday, February 18, 1991.

DEFECT INVOLVED:

On (8) 1991 C7 Trucks equipped with 2-speed rear axles (HRU or GJ4 & HR1) or single speed rear axles with a differential lock (HNG), the lubricant for the rear axles air operated control motor(s) was omitted. Without this lubricant, the control motor will likely fail prematurely, resulting in a 2-speed axle remaining in the high range or the inability to lock the differential.

The correction will consist of adding the required lubricant to the control motor(s).

VEHICLES INVOLVED:

The following VIN's are included in this recall:

1GDS7H4MXMJ502610 1GDS7H4M7MJ500295 1GDS7H4J7MJ502814 1GDS7H4J0MJ500337 1GDS7H4M4MJ501386 1GDS7H4M4MJ503087 1GDS7H4M9MJ500461 1GDS7H4M8MJ500743

PARTS INFORMATION:

Parts required to complete this campaign should be ordered through regular channels, as follows:

Part Number Description Quantity/Vehicle ----------- --------------- ---------------- 5416939 Refrigerant Oil As Required

PARTS AND LABOUR CLAIM INFORMATION:

Credit for the campaign work performed will be paid upon receipt of a properly completed campaign claim card or DCS transmission in accordance with the following:

Repair Code Description Time Allowance ----------- --------------------- --------------- 2A Add Required Lubricant . 3

Time allowance includes 0. 1 hour for dealer administrative detail associated with this campaign. Parts credit will be based on dealer net plus 30% to cover parts handling.

SERVICE PROCEDURE:

Rear Axle Shift Motor

When to Check and What to Use:

If you have an optional air shift two-speed, controlled traction, or locking differential type rear axle, a good time to check the fluid level in the axle shift motor is when the rear axle lubricant is checked. Use refrigerant oil (shift motor only), GM Part Number 5416939.

How to Cheek and Add Fluid:

Remove plug on front plate of axle shift motor and add enough fluid to raise the level to die bottom of the filler plug hole. Replace plug.

INSTALLATION OF CAMPAIGN IDENTIFICATION LABEL

Clean surface of radiator upper mounting panel and apply a Campaign Identification Label. Make sure the correct campaign number is inserted on the label. This will indicate that the campaign has been completed.

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.