CAMPAIGN: 5 SPEED MANUAL TRANS. MAIN SHAFT SEIZURE

SUBJECT: 5-SPEED MANUAL TRANSMISSION MAIN SHAFT SEIZURE

MODELS: 1996 GMC SONOMA 2-WHEEL DRIVE PICKUPS EQUIPPED WITH 2.2L ENGINE AND 5 SPEED MANUAL TRANSMISSION (LN2 & MW2)

IMPORTANT!! -----------

ALL STOCK VEHICLES INVOLVED IN THIS CAMPAIGN WERE PLACED ON STOP SALE/DELIVERY STATUS ON 2/9/96.

AFTER THE CAMPAIGN SERVICE PROCEDURE IS COMPLETED, THE VEHICLES MAY BE SOLD.

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 appointments with owners and to repair their vehicles 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 GMC Division Consumer Relations Office if the dealer does not remedy the condition within seven 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

General Motors has decided that a defect, which relates to motor vehicle safety, exists in CERTAIN 1996 GMC Sonoma 2-wheel drive pickup trucks equipped with 2.2L engines and 5-speed manual transmissions. Some of these trucks have been built with a transmission containing parts not machined to specification. Transmissions built with mismachined parts could seize and lock the rear wheels while the truck is being operated. This could cause a loss of vehicle control and possibly a vehicle crash without prior warning.

To correct this condition, dealers will inspect the transmission main shaft output torque using a special tool. If the output torque does not meet the inspection criteria, the transmission will be replaced.

VEHICLES INVOLVED

Involved are CERTAIN 1996 GMC Sonoma 2-wheel drive pickup trucks equipped with 2.2L engines (LN2) and 5-speed manual transmissions (MW2) built within the following VIN breakpoints:

Plant Year Model Code From Through ---- ----- ------- ----- --------

1996 S Truck K SOP TK512763 1996 S Truck 8 SOP T8509012

The specific vehicles involved in this campaign have been identified by Vehicle Identification Number (VIN) Computer Listings. These listings are furnished to all involved dealers with the campaign. Dealers should confirm vehicle eligibility through VISS (Vehicle Information Service System) or SERVICENET prior to beginning campaign repairs.

DEALER CAMPAIGN RESPONSIBILITY

All unsold vehicles in dealers'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 service all vehicles subject to this campaign at no charge to owners, regardless of mileage, 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 the 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 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.

If the name and address of the owner of an involved vehicle was unavailable to GMC Division at the time of campaign initiation, the dealer must 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 Division General Motors Corporation 101 Union Street Plymouth, Michigan 48170

OWNER NOTIFICATION

Owners will be notified of this campaign on their vehicles by GMC Division (see copy of owner letter included with this bulletin). A listing of owner names and addresses has been fumished 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

Turning torque of the transmission must be measured using special tools supplied to the dealership.

Special Tool Information

The special tool will be pre-shipped to all dealers free of charge. Tools will be shipped by Helm the week of 2/19/96. A replacement tool can be obtained by contacting Adistra at 1-800-627-5699.

Test Procedure

This test procedure must be performed on all involved vehicle transmissions.

1. Raise and support the vehicle with the frame level to the ground.

2. Remove the transmission fluid fill plug and verify that transmission fluid level is full.

3. Measure transmission fluid temperature using thermometer J6742-03 (Figure 1) or equivalent. Fluid temperature must be between 50 and 100 degrees F. Temperatures outside this range can produce inaccurate results.

4. Remove the propeller shaft.

5. Install the special tool to the transmission output shaft (Figure 2). Do not bottom the tool on the extension seal as this could produce inaccurate results or damage the seal.

CAUTION:

The special tool can slide out of the transmission and fall to the floor causing possible personal injury. Be sure you hold onto the when the clutch pedal is depressed.

*** An assistant must be in the truck cab to accomplish the next 7 steps.***

6. The assistant should stroke the clutch pedal six (6) times and hold the pedal to the floor for the next 5 steps.

7. The assistant should shift the truck into Reverse and take his hand off the shift lever.

8. Rotate the special tool clockwise and counter clockwise six (6) times to assure that the clutch disc and the synchronizer blocker rings are fully released.

9. Position the special tool so that it is stationary at 9 o'clock.

10. Release the special tool and observe whether the weighted end begins to rotate downward.

If the weight begins to rotate, the transmission is O.K. Proceed to step 11.

If the weight does NOT begin to rotate, the transmission must be replaced. Proceed to Transmission Replacement Procedure listed below.

IMPORTANT: The weighted end will not rotate to a complete vertical position. Any movement of the weighted end is sufficient.

11. Repeat steps 8, 9 and 10 with the transmission in lst gear. Be sure the clutch pedal remains depressed to the floor and the assistant's hand is removed from the shift lever.

- If the weight begins to rotate, the transmission is O.K. Proceed to step 12.

- If the weight does NOT begin to rotate, the transmission must be replaced. Proceed to Transmission Replacement Procedure listed below.

IMPORTANT: The weighted end will not rotate to a complete vertical position. Any movement of the weighted end is sufficient.

12. Remove the special tool and install the propeller shaft. Torque the pinion flange bolts to 20 Nm (15 lb. ft.) and the center bearing support bolts to 70 Nm (50 lb. ft.).

13. Verify that the transmission fluid level is full. Install the transmission fluid fill plug.

14. Lower the vehicle.

15. Install Campaign Identification Label.

Transmission Replacement Procedure

Transmission replacement is required only when the special tool did NOT begin to rotate in either First or Reverse.

1. The transmission must be replaced following the transmission replacement procedure as detailed in the 1996 S/T Truck Service Manual, Book 1 of 2 (GMT/96-ST-1). Refer to Manual Transmission Section 7B-6, Transmission Replacement for the proper procedure.

2. Drain the transmission fluid before removing the transmission from the vehicle.

The following components should be removed from the transmission being returned:

- Concentric slave cylinder - Transmission mount

The following components should remain on the transmission being returned:

- Shift housing (shift tower/stub shaft) - Back-up lamp switch - VSS

IMPORTANT: The exchange transmission will be shipped filled with fluid. If additional fluid is necessary, this transmission MUST use Manual Transmission Fluid, P/N 12377916, because it contains a special friction modifier. Other fluids should not be substituted as they may result in poor shift quality. Fluid capacity is 2.OL (2.2 Qts.).

3. Install Campaign Identification Label.

PARTS INFORMATION

Transmissions must be obtained through New Venture Gear (NVG). DO NOT ORDER TRANSMISSIONS FROM GMSPO. Contact NVG at 1-800-417-9556 to order or ship a transmission. This phone number will be answered from 8:00 a.m. through 7:00 p.m. EST, Monday through Friday, and 8:00 a.m through 2:00 p.m. EST, Saturday. Unsold units will receive a new transmission, sold units will receive a remanufactured transmission.

Obtaining A Transmission

1. Once you have tested the transmission with the special tool provided, call NVG at 1-800-417-9556 to order a transmission.

2. NVG will obtain dealership name and shipping information as well as the VIN. The replacement transmission will be shipped to arrive within 48 hours.

Replacement transmissions will be marked with the last eight digits of the vehicle VIN. Transmissions will also be marked with a color dot to indicate if they are new or remanufactured. New transmissions will be marked with a green dot, remanufactured transmissions will be marked with a yellow dot.

Returning A Transmission

IMPORTANT: Removed transmissions must be shipped to NVG immediately to avoid a charge-back. Failure to return the transmission will result in the dealership being billed $1,000 which is the value of the exchange transmission.

1. All oil must be drained from the transmission being returned. Remove shipping plugs from the replacement transmission and install them on the return transmission.

2. Use a marker to write the last eight digits of the VIN on the removed transmission.

3. The shipping container from the replacement transmission is to be used for return shipments to NVG. A pre-printed shipping label is included with the replacement transmission. This label should be used on the shipping container.

4. After the transmission is packaged in the shipping container, call NVG at 1-800-417-9556 to return a transmission. NVG will contact the carrier, schedule the pickup, and pay for shipping.

Part Number Description Quantity ----------- ----------- --------

12377916 Manual Transmission Fluid As Required

Dealers need to order the transmission fluid from GMSPO as required.

If an additional special tool is needed due to loss, call Adistra at 1-800-627-5699 and request part number 96C20PART. DO NOT ORDER SPECIAL TOOL FROM GMSPO.

WARRANTY INFORMATION

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

Description CC FC Op Hrs Item

Inspect Transmission Turning MA 96 V9893 0.6 ** Torque - No Further Action Required

Inspect and R & R Transmission MA 96 9894 2.6 *** (includes moving vehicle in & out of stall)

Courtesy Transportation MA 96 T2498 --- +

* For Campaign Administrative Allowance, add 0.1 hours to the "Labor Hours". Add an additional 0.1 hours if transmission is replaced to cover packaging transmission for shipment.

** Net Item column to include actual cost of transmission fluid used, plus 40% mark-up.

*** Net Item column to include actual cost of transmission fluid used, plus 40% markup; plus $406.20 which is the markup for the transmission furnished for this campaign.

+ Courtesy Transportation "Net Amount" only valid with Labor Op V9894, Inspect and R&R Transmission.

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 five (5) digit dealer code of the dealer performing the campaign service. This information must be inserted with a typewriter or ball point pen. This label is to be used in conjunction with the clear protective plastic cover provided with the Campaign Identification Labels.

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.

Additional Campaign Identification Labels and covers are available in sheets of 49 by calling VISPAC, Incorporated at 1-800-269-5100 (Monday through Friday 8:00 AM to 4:30 PM EST).

ADMINISTRATIVE PROCEDURE

Procedures covering this campaign are outlined in Section IV of your dealership's "WINS Claims Processing Manual".

Dear GMC Sonoma Customer,

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

Reason For This Recall

General Motors has decided that a defect, which relates to motor vehicle safety, exists in CERTAIN 1996 GMC Sonoma 2-wheel drive pickup trucks equipped with 2.2L engines and 5-speed manual transmissions. Some of these trucks have been built with a transmission containing parts not machined to specification. Transmissions built with mismachined parts could seize and lock the rear wheels while the truck is being operated. This could cause a loss of vehicle control and possibly a vehicle crash without prior warning.

What We Will Do

Transmissions with potential to seize generally do so in less than 500 miles of use. To correct this condition your GMC dealer will inspect your transmission and replace it if necessary. This service will be performed for you at no charge.

What You Should Do

If your vehicle has been driven less than 3200 miles take it immediately to your GMC dealer for inspection. If the inspection shows your transmission requires replacement and that service cannot be completed that day, a loaner vehicle will be provided for your use until your transmission is replaced. Instructions for making this correction have been sent to your dealer and parts are available. The labor time to perform the inspection is approximately 40 minutes. Labor time to replace your transmission, if required, is approximately 2 and 1/2 hours. Please ask you dealer if you wish to know how much additional time will be needed to schedule and process your vehicle.

Your GMC dealer is best equipped to obtain parts and provide service to ensure your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date and they do not remedy this condition on that date or within seven (7) days, we recommend you contact the GMC Customer Assistance Center by calling 1-800-462-8782. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and 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 1-800-424-9393 (Washington, D.C. residents use 202- 366-0123).

The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returing 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 roducts.

GMC Division 96C20 General Motors Corporation Enclosure

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.