CAMPAIGN: SOFT 1-2 UPSHIFT A/T CLUTCH SLOW TO ENGAGE
MODELS: 1982 CK 25-35 SERIES TRUCKS WITH RPO LL4 (HEAVY DUTY 6.2L DIESEL ENGINE) AND RPO MX1 (THM 400 TRANSMISSION)
General Motors has determined that some early production 1982 CK 25-35 Series Trucks with RPO LL4 (Heavy Duty 6.2L Diesel Engine) and MX1 (THM 400 Transmission) may experience a transmission clutch which is slow to engage, a condition which may not be detectable to the vehicle operator.
To prevent the possibility of this condition occurring, it will be necessary to adjust the engine vacuum regulator setting and install a new vacuum modulator on the transmission assembly according to the instructions contained in this bulletin. If this condition is not corrected, premature transmission clutch wear may occur.
VEHICLES INVOLVED
Involved are some early production 1982 CK 25-35 Series Trucks with RPO LL4 (Heavy Duty 6.2L Diesel Engine) and RPO MX1 (THM 400 Transmission) within the following parameters:
Plant
St. Louis 4 Vehicles Only CS500220 CS500652 CS500656 CS500660
Pontiac From CV555766 Through CV557962
The specific vehicles involved in this campaign have been identified by Vehicle Identification Number Computer Listings. These listings are furnished 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.
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 & Coach Division 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 Home Office, Attn: Campaign Coordinator.
GMC Truck & Coach 660 South Boulevard East Pontiac, Michigan 48053
OWNER NOTIFICATION
Owners will be notified of this campaign on their vehicles by GMC Truck & Coach Division (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
A. Transmission-Vacuum Modulator Inspection and/or Replacement.
1. Raise vehicle.
2. Inspect vacuum modulator.
If the vacuum modulator is white, no further action is required.
If vacuum modulator is black, replace with P/N 359917.
Replacement procedure for vacuum modulator may be found in the 1982 GMC Service Manual Light Duty Trucks, X-8232, Section 7A-57.
3. Lower vehicle.
B. Engine-Vacuum Regulator Reset Procedure.
1. Open hood and remove air cleaner.
2. Locate the vacuum regulator (on the forward end of the fuel injection pump).
3. Loosen both vacuum regulator holding screws to finger loose. Do Not Remove The Screws. Refer to Figure No. 1.
4. Rotate the valve full clockwise.
5. Tighten both vacuum regulator holding screws to 7-11 N.m. (5.2 - 8.1 lb. ft.).
6. Do not adjust any other screws.
7. Install air cleaner.
PARTS INFORMATION
Parts required to complete this campaign are to be ordered by the dealer from the Warehousing and Distribution Division of General Motors (WDDGM).
Quantity Part Number Per Vehicle Description
359917 1 Modular (White)
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
V1190 Reset engine .3 96 vacuum regulator and inspect trans- mission vacuum modulator. No further action required.
V1191 Reset engine .5 96 vacuum regulator and install new transmission vacuum modulator.
*For dealer to receive Administration Time Allowance associated with this campaign, add 0.1 hour to the Labor Operation Time Allowance.
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:
General Motors has determined that some early production 1982 CK 25-35 Series Trucks with RPO LL4 (Heavy Duty 6.2L Diesel Engine) and RPO MX1 (THM 400 Transmission) may experience a transmission clutch which is slow to engage, a condition which may not be detectable to the vehicle operator.
To prevent the possibility of this condition occurring on your vehicle, it will be necessary to adjust the engine vacuum regulator setting and install a new vacuum modulator on the transmission assembly. If this condition is not corrected, premature transmission clutch wear may occur.
Instructions have been sent to your GMC Truck Dealer. Please contact your dealer to arrange a service date to have the engine vacuum regulator setting adjusted and the transmission vacuum modulator inspected, and if required, replaced. The labor time to perform the modification is approximately thirty (30) minutes. The modification will be performed at no charge to you.
The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist him in making the necessary correction to your vehicle in the shortest possible time. 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 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.
