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For 1990-2009 cars only

CAMPAIGN:AUTOMATIC TRANSMISSION OVERHEAT

SUBJECT: AUTOMATIC TRANSMISSION OIL OVERHEAT

MODELS: 1991-1993 Chevrolet/GMC C 3500 HD Models (C31003/31403 W/C5B, C31803) Equipped With Automatic Transmission (MT1)

TO: ALL GENERAL MOTORS DEALERS

General Motors of Canada Limited has determined that certain 1991-1993 Chevrolet/GMC C 3500 HD model vehicles equipped with automatic transmissions (MT1) may overheat the transmission off during certain operating conditions. Overheating oxidizes the transmission oil and reduces its useful life. If these operating conditions occur often enough, they can reduce the life of the transmission.

To prevent this condition from occurring, dealers will inspect and, if necessary, install an external transmission oil cooler.

VEHICLES INVOLVED:

Involved are certain 1991-1993 Chevrolet/GMC C 3500 HD (C31003/31403 W/C5B, C31803) model vehicles equipped with automatic transmission built within the following breakpoints:

CHEV Year Model From Through

1991 C 3500 HD SOP EOP

1992 C 3500 HD SOP EOP

1993 C 3500 HD SOP PJ108606

GMC Year Model From Through

1991 C 3500 HD SOP EOP

1992 C 3500 HD SOP EOP

1993 C 3500 HD SOP PJ516578

NOTE: PLEASE CHECK DCS SCREEN 45 OR YOUR V.I.N. LISTING BEFORE PERFORMING CAMPAIGN TO ENSURE THAT THE VEHICLE IS AFFECTED. ONLY AFFECTED VIN'S WILL BE PAID.

All affected vehicles have been identified by the VIN listing provided to involved dealers with this bulletin. Any dealer not receiving a listing was not shipped any of the affected vehicles.

DEALER CAMPAIGN RESPONSIBILITY:

All unsold new vehicles in dealer's possession and subject to this campaign must be held and inspected/repaired per the Service Procedure of this Campaign Bulletin before owners take possession of these vehicles.

Dealers are to perform this campaign on all involved vehicles at no charge to owners, regardless of kilometers traveled, age of vehicle, or ownership, from this time forward.

Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to instructions contained in this bulletin. This could be done by mailing to such owners a copy of the owner letter accompanying this bulletin. Campaign follow- up cards should not be used for this purpose, since the owner may not as yet have received the notification letter.

In summary, 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, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle.

CAMPAIGN PROCEDURE:

Refer to Section 4 of the Service Policies and Procedures Manual for the detailed procedure on handling Product Campaigns. Dealers are requested to complete the campaign on all transfers as soon as possible.

OWNER NOTIFICATION:

All owners of record at the time of campaign release are shown on the attached computer listing and have been notified by first class mail from General Motors (see copy of owner letter included with this bulletin). The listings provided are for campaign activity only and should not be used for any other purpose.

PARTS INFORMATION:

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

Part Number Description Quantity/Vehicle ----------- ----------- ---------------- 12546253 Cooler Kit, Trans. Oil 1

10952622 Fluid, Auto Trans. As Required Dexron III, 1 Liter

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 ----------- ----------- -------------- 1A Inspect-Vehicle equipped with GM .2 Transmission Oil Cooler, installed by GM at no charge to customer

2A Inspect-Vehicle has no Transmission Oil 1.2 Cooler, customer requests GM Cooler - Install Cooler

3A Inspect-Vehicle equipped with an Aftermarket .2 Transmission Oil Cooler which was installed at customer expense, customer does not want GM Cooler. Reimbursement not available.

4A Inspect, Remove and Install-Vehicle equipped 1.7 with Aftermarket Transmission Oil Cooler which was installed at customer expense, customer requests GM Cooler. See Reimbursement Section (use 7A for the reimbursement)

6A Inspect-Vehicle equipped with GM .2 Transmission Oil Cooler which was installed at customer expense, customer requests reimbursement See Reimbursement Section

NOTE: Repair Code 4A includes .5 hours for removal of existing Transmission Oil Cooler.

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:

To install the cooler kit, the radiator grille must be removed. Refer to the appropriate Chevrolet/GMC C/K service manual, Sheet Metal Section 2B, for radiator grille R & R procedure. Transmission cooler installation instructions are included in every kit. After installing the transmission oil cooler the transmission fluid level should be checked and adjusted to the correct operating level as specified in the appropriate C/K Service Manual.

If the vehicle already has an aftermarket transmission oil cooler, and the owner does not want the GM Cooler installed, the campaign should be closed as completed. No reimbursement should be provided as noted in the Reimbursement Section of this bulletin.

Note: Make sure there are no sharp edges on the end of the transmission cooler metal lines. Sharp edges can cut the inside of the cooler hose causing a leak and possible transmission damage.

REIMBURSEMENT

If an external transmission cooler has been installed on the vehicle at the owner's expense, and if the owner so requests, GM dealers will replace it with the GM cooler and reimburse the owner the cost of purchase and installation up to $186.00.

When the customer requests reimbursement, the following must accompany the request and be attached to the repair order file copy in the dealership:

- Proof of ownership and

- Original documentation that confirms amount of external transmission cooler purchase and installation expense, the date of purchase/installation and the place of purchase/installation.

If the vehicle owner already has an aftermarket external transmission cooler, and the owner does not want the GM cooler installed, the campaign should be closed as completed. N o reimbursement should be provided.

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.

Dear General Motors Customer:

General Motors of Canada Limited has determined that certain 1991-1993 Chevrolet/GMC C 3500 HD model vehicles equipped with automatic transmissions may overheat the transmission oil during certain operating conditions. Overheating oxidizes the transmission oil and reduces its useful life. If these operating conditions occur often enough, they can reduce the life of the transmission.

To prevent this condition from occurring, your dealer will inspect and, if necessary, install an external transmission oil cooler.

This service will be provided for you at no charge.

Please contact your GM dealer as soon as possible to arrange a service date.

If parts are required, ask your dealer for details regarding their availability. If parts are not in stock, they can be ordered before scheduling your service date.

This letter identifies your vehicle. Presentation of this letter to your dealer will assist their Service personnel in completing the necessary correction to your vehicle in the shortest possible time.

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

Customer Support Department General Motors of Canada Limited

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.