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CAMPAIGN: CRANKSHAFT BALANCER CENTRE BOLT TORQUE

NOTE: GM OF CANADA CAMPAIGN 96057 IS LOCATED BELOW THE U.S. VERSION

CUSTOMER SATISFACTION CAMPAIGN

SUBJECT: 96057 - CRANKSHAFT BALANCER CENTER BOLT TORQUE ----------------------------------------------

MODELS: 1996 C/K TRUCKS WITH 7.4L GAS ENGINES (L29) BUILT AT FORT --------------------------------------------------------- WAYNE ASSEMBLY --------------

General Motors has decided that certain 1996 C/K trucks equipped with 7.4L gasoline engines (L29) and built at the Fort Wayne Assembly plant may have a crankshaft balancer center-attaching bolt that was under-torqued. This bolt secures the balancer, which is pressed onto the crankshaft, and the accessory drive pulley, which is attached to the damper, to the engine crankshaft. If this bolt were to completely loosen, the balancer press fit would begin to loosen. This loosening would likely manifest itself as accessory drive-belt noise, soon followed by the drive belt coming off the pulley or breaking, which would cause a loss of drive to the engine accessories. Additionally, the loosening of the balancer-pulley assembly would likely damage the crankshaft.

To prevent the possibility of this condition occurring, dealers are to torque the crankshaft balancer center bolt up to the specified torque.

VEHICLES INVOLVED

Involved are certain 1996 C/K trucks built at Fort Wayne Assembly plant equipped with 7.4L gasoline engines (L29) and built within the following VIN breakpoints:

YEAR DIVISION MODEL PLANT CODE FROM THROUGH ---- -------- ---- ----- ---- --------- ------- 1996 GMC C/K Fort Wayne "Z" TZ515235 TZ526487 1996 Chevrolet C/K Fort Wayne "Z" TZ155511 TZ176341

NOTICE: Dealers should confirm vehicle eligibility through VISS ( vehicle Information Service System) or ServiceNet (GMC only) prior to beginning campaign repairs. [Not all vehicles within the above breakpoints may be involved]

Involved vehicles have been identified by Vehicle Identification Number. Computer listings containing the complete Vehicle Identification Number, customer name and address data have been prepared, and are being furnished to involved dealers with the campaign bulletin. The Customer name and address data furnished will enable dealers to follow-up with customers involved in this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned.

These dealer listings may contain customer 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 the follow-up necessary to complete this campaign.

PARTS INFORMATION

No parts are required for this campaign.

CUSTOMER NOTIFICATION

Customers will be notified of this campaign on their vehicles by General Motors (see copy of divisional customer letter(s) included with this bulletin).

DEALER CAMPAIGN RESPONSIBILITY

All unsold new vehicles in dealers' possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before customers take possession of these vehicles.

Dealers are to service all vehicles subject to this campaign at no charge to customers, regardless of mileage, age of vehicle, or ownership, from this time forward.

Customers who have recently purchased vehicles sold from your vehicle inventory, and for which there is no customer information indicated on the dealer listing, are to be contacted by the dealer. Arrangements are to be made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such customers a copy of the appropriate divisional customer letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the customer may not as yet have received the notification letter.

In summary, whenever a vehicle subject to this campaign enters your 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.

SERVICE PROCEDURE

1. Raise vehicle.

2. Remove exhaust crossover pipe.

3. Remove flywheel inspection cover.

4. Torque crankshaft pulley/balancer bolt (Figure 1, Item 1) to 149 Nm (110 Ft. Lb.) using two technicians, one holds flywheel).

5. Install flywheel inspection cover.

6. Install exhaust crossover.

7. Lower vehicle.

8. Install the GM Campaign Identification Label.

CAMPAIGN IDENTIFICATION LABEL

Each vehicle corrected 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 campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point 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 by the by the customer for periodic servicing.

When installing the Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering.

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

CLAIM INFORMATION

Submit a Product Campaign Claim with the information indicated below:

* REPAIR PART FAILED PARTS LABOR LABOR PERFORMED COUNT PART NO. ALLOW CC-FC 0P HOURS

Torque Crankshaft --- --- --- MA-96 V9958 0.6 Balancer Center Bolt

* For Campaign Administrative Allowance, add 0.1 hours to the "Labor Hours".

Refer to the General Motors Corporation Claims Processing Manual for details on Product Campaign Claim Submission.

October, 1996

Dear GM Truck Customer:

As a valued customer, your complete satisfaction with your GM truck is our goal. In keeping with this goal, we want to let you know that we have discovered a problem that could affect your vehicle and we want to take care of it at no charge to you.

On certain 1996 C/K model trucks equipped with a 7.4L gasoline engine, such as yours, the crankshaft balancer center-attaching bolt may have been under torqued. This bolt secures the balancer, which is pressed onto the crankshaft, and the accessory drive pulley, which is attached to the balancer, to the engine crankshaft. If this bolt were to completely loosen, the balancer press fit would begin to loosen. This loosening would likely manifest itself as accessory drive belt noise, soon followed by the drive belt corning off the pulley or breaking, which would cause a loss of drive to the engine accessories. Additionally, the loosening of the balancer-pulley assembly would likely damage the crankshaft.

To be absolutely sure that your vehicle is to specifications, we will torque the crankshaft balancer center bolt up to the specified torque.

Instructions for performing this service have been, sent to your GM dealer. Please contact your GM dealer to arrange a service date as soon as possible. This procedure will take about 40 minutes to complete, but you should ask how much additional time your dealer will need to schedule and process your vehicle.

The enclosed postage paid owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction to your vehicle in the shortest possible time. If you have sold or traded your vehicle, please furnish us the complete name and address of the person you sold or traded your vehicle to and retum the card to us.

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

GENERAL MOTORS CORPORATION

** CANADIAN VERSION **

CUSTOMER SATISFACTION CAMPAIGN

SUBJECT: CAMPAIGN 96057 - CRANKSHAFT BALANCER CENTRE BOLT TORQUE -------------------------------------------------------

MODELS: 1996 C/K TRUCKS WITH 7.4L GAS ENGINES (L29) BUILT AT FORT WAYNE --------------------------------------------------------------- ASSEMBLY --------

DEFECT INVOLVED

General Motors of Canada Limited has decided that certain 1996 C/K trucks equipped with 7.4L gasoline engines (L29) and built at the Fort Wayne Assembly plant may have a crankshaft balancer centre-attaching bolt that was under-torqued. This bolt secures the balancer, which is pressed onto the crankshaft, and the accessory drive pulley, which is attached to the balancer, to the engine crankshaft. If this bolt were to completely loosen, the balancer press fit would begin to loosen. This loosening would likely manifest itself as accessory drive-belt noise, soon followed by the drive belt coming off the pulley or breaking, which would cause a loss of drive to the engine accessories. Additionally, the loosening of the balancer-pulley assembly would likely damage the crankshaft.

To prevent the possibility of this condition occurring, dealers are to torque the crankshaft balancer centre bolt up to the specified torque.

VEHICLES INVOLVED

Involved are certain 1996 C/K trucks built at Fort Wayne Assembly plant equipped with 7.4L gasoline engines (L29) and built within the following VIN breakpoints:

PLANT YEAR DIVISION MODEL PLANT CODE FROM THROUGH ---- -------- ----- ----- ----- ---- -------- 1996 GMC C/K Fort Wayne "Z" TZ515235 TZ326487 1996 Chevrolet C/K Fort Wayne "Z" TZ155511 TZ176341

NOTE: PLEASE CHECK DCS SCREEN 445 OR YOUR V.I.N. LISTING BEFORE PERFORMING CAMPAIGN TO ENSURE THAT THE VEHICLE IS AFFECTED. ONLY AFFECTED VIN'S WILL BE PAID.

Involved vehicles have been identified by Vehicle Identification Number. Computer listings containing the complete Vehicle Identification Number, customer name and address data have been prepared, and are being furnished to involved dealers with the campaign bulletin. The customer name and address data furnished will enable dealers to follow-up with customers involved in this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned.

PARTS INFORMATION

No parts are required for this campaign.

CUSTOMER NOTIFICATION

All customers 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 customer letter included with this bulletin). The listings provided are for campaign activity only and should not be used for any other purpose.

DEALER CAMPAIGN RESPONSIBILITY

All unsold new vehicles in dealers' possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before customers take possession of these vehicles.

Dealers are to service all vehicles subject to this campaign at no charge to customers, regardless of mileage, age of vehicle, or ownership, from this time forward.

Customers who have recently purchased vehicles sold from your vehicle inventory, and for which there is no customer information indicated on the dealer listing, are to be contacted by the dealer. Arrangements are to be made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such customers a copy of the appropriate customer letter accompanying this bulletin.

In summary, whenever a vehicle subject to this campaign enters your vehicle inventory, or is in your dealership for service in the future, you must take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle.

SERVICE PROCEDURE

1. Raise vehicle.

2. Remove exhaust crossover pipe.

3. Remove flywheel inspection cover.

4. Torque crankshaft pulley/balancer bolt (Figure 1, Item 1) to 149 Nm (110 Ft. Lb. ) (using two technicians, one holds flywheel).

5. Install flywheel inspection cover.

6. Install exhaust crossover.

7. Lower vehicle.

8. Install Campaign Identification Label.

CAMPAIGN IDENTIFICATION LABEL

Each vehicle corrected 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 campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point 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 by the customer for periodic servicing. Additional Campaign Identification Labels can be obtained from DGN by calling 1-800-668-5539 (Monday-Friday, 8:00 a.m. to 5:00 p.m. EST). Ask for Item Number GMP 91 when ordering. Apply the "Campaign Identification Label" only on a clean, dry surface.

CLAIM INFORMATION

Submit a Product Campaign Claim with the information indicated below:

* REPAIR PERFORMED PART FAILED PARTS LABOUR LABOUR COUNT PART NO. ALLOW CC-FC 0P HOURS -------------------------- ----- -------- ----- ----- ------ ------ Torque Crankshaft Balancer - - - MA-96 V9958 0.6 Centre Bolt

* For Campaign Administrative Allowance, add 0. I hours to the "Labour Hours".

Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission.

General Motors of Canada Limited September 1996

Dear General Motors Customer:

As a valued customer, your complete satisfaction with your GM vehicle is our goal. In keeping with this goal, we want to let you know that we have discovered a problem that could affect your vehicle and we want to take care of it at no charge to you.

On certain 1996 GMC Sierra and Chevrolet Silverado model vehicles equipped with a 7.4L gasoline engine, such as yours, the crankshaft balancer centre-attaching bolt may have been under-torqued. This bolt secures the balancer, which is pressed onto the crankshaft, and the accessory drive pulley, which is attached to the balancer, to the engine crankshaft. If this bolt were to completely loosen, the balancer press fit would begin to loosen. This loosening would likely manifest itself as accessory drive belt noise, soon followed by the drive belt coming off the pulley or breaking, which would cause a loss of drive to the engine accessories. Additionally, the loosening of the balancer-pulley assembly would likely damage the crankshaft.

To be absolutely sure that your vehicle is to specifications, your GM dealer will torque the crankshaft balancer centre bolt up to the specified torque.

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


Object Number: 96420  Size: FS

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.