CAMPAIGN: DIFFERENTIAL SHAFT LOCK SCREW LOOSENING

MODELS: 1982 C,K 15 AND G15 - 25 LIGHT DUTY TRUCKS EQUIPPED WITH RPO G80 (8.50") EATON LOCKING DIFFERENTIAL

THIS BULLETIN SUPPLEMENTS BULLETIN 82-C-10, ISSUED OCTOBER, 1982. VEHICLES WHICH HAVE ALREADY BEEN CORRECTED WILL REQUIRE NO FURTHER ACTION.

The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle which is subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to adequately repair within 60 days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time.

If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonably equivalent vehicle at no charge, or to a refund of the purchase price less a reasonable allowance for depreciation.

To avoid having to provide these burdensome solutions, every effort must be made to promptly schedule a service date with each owner and to repair their vehicle as soon as possible. As you will see in reading the attached copy of the letter which is being sent to owners, the owner is being instructed to contact the nearest GMC Zone Office if their dealer does not remedy the condition within five days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed how to contact the National Highway Traffic Safety Administration.

DEFECT INVOLVED

In October, 1982, General Motors notified owners that a defect existed on some 1982 C,K15 and G15- 25 Series Light Duty Trucks equipped with 8.5" Eaton locking differentials (RPO G80). In that notification, owners were advised that on these trucks the differential lock screw or differential pinion shaft could come loose and damage the rotating parts of the rear axle.

The National Highwaytraffic Safety Adminstration (NHTSA) has advised General Motors that this defect "could result in a loss of vehicle control and an accident." Acordingly, the NHTSA has requested General Motors to initiate a safety recall to notify the owners whose vehicles have not yet been corected "of the problem and its consequences." Based on this request, General Motors has reconsidered this matter and has determined that a defect which relates to motor vehicle safety exists on some 1982 C,K15 and G15-25 Series Light Duty Trucks equipped with 8.5" Eaton locking differentials (RPO G80). On these trucks, the differential lock screw or differential pinion shaft could come loose. If this were to occur while the vehicle is in motion, it could result in "a loss of vehicle control and an accident."

To prevent the possibility of this condition occurring, GMC Truck Dealers are to replace the differential lock screw on these vehicles in accordance with the Service Procedure in this bulletin.

VEHICLES INVOLVED

Involved are certain 1982 C,K15 and G15-25 Series Light Duty GMC Trucks equipped with RPO G80 (8.50") Eaton locking differential assembled at the following assembly plants within these param- eters:

Plant From Through ----- ---- ------- St. Louis Start of Production CS517267 Janesville Start of Production CJ509531 Lordstown Start of Production C7504427 Flint #1 Start of Production CF709647 Flint #2 Start of Production CF516834 Oshawa Start of Production C1527899 Scarborough Start of Production C4516657 Fremont Start of Production CZ501619

The speciic vehicles involved in this campaign have been identified by Vehicle Identification Number Computer Listings. These listings are fur- nished to all involved dealers with the campaign bulletin.

DEALER CAMPAIGN RESPONSIBILITY

Dealers are to service all vehicles subject to this campaign regardless of mileage, age of vehicle, or ownership from this time forward.

Whenever a vehicle subject to this campaign is taken into your new or used vehicle inventory or is in your dealership for service in the future, you should take the steps necessary to be sure the campaign correction has been made before reselling the vehicle.

On vehicles involved in this campaign that have been recently sold to a retail owner, where no owner's name and address were available to GMC Truck at the time of campaign initiation, the dealer will determine the owner's name and address from the dealership sales records. Please provide this information directly on the second copy of the listing next to the applicable VIN, so that our records may be updated and the appropriate notification mailed to the owner. This second copy should then be submitted to the address listed below in the previously supplied yellow campaign envelopes.

GMC Truck General Motors Corporation 101 Union Street Plymouth, Michigan 48170

OWNER NOTIFICATION

Owners will be notified of this campaign on their vehicles by GMC Truck (see copy of Owner Letter included with this bulletin). A listing of owner names and addresses has been furnished to the involved dealers to enable dealers to follow up with owners involved in this campaign. This listing may contain owner names and addresses obtained from state motor vehicle registration records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to this campaign.

SERVICE PROCEDURE

Inspection

1. Raise vehicle on hoist.

2. Inspect rear axle code stamped on top of right axle tube outboard of carrier.

KHA G 001 1

Axle & Source Date Shift Vehicle Code Code Code Code

G = Gear Jan. 1 = 001 1st & Axle Shift

A. When the source code is "W", "C" or "K", lower the vehicle and install the campaign completion label. No further action is required.

B. When the source code is "G", proceed with the following modification.

3. Clean all dirt from around carrier cover.

4. Drain lubricant from carrier by removing cover.

5. Rotate the case to the position shown in Figure 1. Support the differential pinion shaft so that it cannot fall into the case and remove the differential pinion shaft lock screw and discard.

6. Clean the case assembly of any excessive lubricant in the threaded area of the lock screw hole.

7. Install new lock screw P/N 14056196, which is coated with an adhesive patch, and torque to 25 ft. lb.

8. Clean the carrier and cover of any old gasket material.

9. Install new gasket, P/N 3993593, and torque cover attaching bolts to 20 ft. lbs. Torque carrier cover bolts in a clockwise pattem to insure uniform draw on cover gasket.

10. Fill axle with 4.2 pints of lubricant, P/N 1052271 (24 oz. container) or P/N 1052272 (15 gal. container).

11. Lower vehicle.

VEHICLE MUST REMAIN STATIONARY FOR AT LEAST TWO (2) HOURS FOLLOWING SERVICING INVOLVING LOCK SCREW INSTALLATION TO INSURE CURING OF ADHESIVE ON SCREW THREADS. HOWEVER, VEHICLE CAN BE MOVED FROM SERVICE AREA TO AN ONSITE PARKING AREA IF SUCH DRIVING IS MODERATE AND PERFORMED IMMEDIATELY AFTER COMPLETION OF AXLE SERVICING.

WARRANTY INFORMATION

Dealers should submit an accurately filled out Warranty Repair order on each vehicle completed under this campaign.

Labor *Time Operation Allow- Trouble Number Description ance Code ------ ----------- ---- ---- V1401 Inspect rear axle 0.2 hr. 96 assembly for source code. Code not requiring pinion shaft lock screw replacement as identified in this bunetin indicate no further action required.

V1400 Replace pinion 0.5 hr. 96 shaft lock screw according to the instructions contained in this bulletin.

*Dealer to receive Administration Time Allowance associated with this campaign, add 0.1 hour to the Labor Operation Time Allowance.

PARTS INFORMATION

Parts required to complete this campaign are to be obtained by the dealer from your Warehousing and Distribution Division of General Motors.

Quantity Part Number Per Vehicle Description ----------- ------------ ------------ 14056196 1 Pinion Shaft Lock Screw

3993593 1 Cover Gasket

1052271 or 4.2 Pints Lubricant 1052272

CAMPAIGN IDENTIFICATION LABEL

Each vehicle modified in accordance with the instructions outlined in this product campaign bulletin will require a "Campaign Identification Label". Each label provides a space to include the five (5) digit Dealer Code of the dealer performing the campaign service. This information may be inserted with a typewriter or ballpoint pen.

Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner.

Apply "Campaign Identification Label" only on a clean dry surface.

ADMINISTRATIVE PROCEDURE

Procedures covering this campaign are outlined in Section V of your dealership's "GMC Truck Claims Processing Manual" issued October, 1981.

Dear GMC Truck Owner:

This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act.

In October, 1982, General Motors notified owners that a defect existed on some 1982 C,K15 and G15-25 Series Light Duty Trucks equipped with 8.5" Eaton locking differentials (RPO G80). In that notification, owners were advised that on these trucks, the differential lock screw or differential pinion shaft could come loose and damage the rotating parts of the rear axle.

The National Highway Traffic Safety Administration (NHTSA) has advised General Motors that this defect "could result in a loss of vehicle control and an accident." Accordingly, the NHTSA has requested General Motors to initiate a safety recall to notify the owners whose vehicles have not yet been corrected "of the problem and its consequences." Based on this request, General Motors has reconsidered this matter and has determined that a defect which relates to motor vehicle safety exists on some 1982 C,K15 and G15-25 Series Light Duty Trucks equipped with 8.5" Eaton locking differentials (RPO G80). On these trucks, the differential lock screw or differential pinion shaft could come loose. If this were to occur while the vehicle is in motion, it could result in "a loss of vehicle control and an accident."

To prevent the possibility of this condition occurring on your vehicle, please contact your GMC Truck dealer to arrange a service date to have the differential lock screw on your vehicle replaced. Instructions for making this correction have been sent to your GMC Truck dealer and the parts have been available since October 20, 1982. This service will be performed at no charge to you. The labor time necessary to perform this correction is approximately one half hour. Please allow additional time for the dealer to process your vehicle.

Your GMC Truck dealer is best equipped to obtain parts and provide service to ensure your vehicle is corrected as promptly as possible. However, if you take your vehicle to your dealer on the agreed service date and they do not remedy this condition on that date or within five days, we recommend you contact your nearest GMC Truck Zone Office, either in person or by telephone. The zone office will assist you and the dealer in getting your vehicle corrected. The locations and telephone numbers of the zone offices are listed in your Owner's Manual.

After contacting your dealer and the zone office, if you are still not satisfied that we have done our best to remedy this condition without charge within a reasonable time, you may wish to write the Administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590, or call 800/424-9393 (Washington, D.C. residents use 426-0123). The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist them in making the necessary correction to your vehicle in the shortest possible time. If you received a previous notification of this condition and have had your vehicle corrected by your dealer or if you have sold or traded your vehicle, please let us know by completing the postage paid owner reply card and returning it to us.

We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your safety and continued satisfaction with our products.

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.