CAMPAIGN:TRANSFER CASE LEAK REPLACE MACHINED ADAPTERS

General Motors has determined that transmission fluid may leak from the transfer case adapter where it meets the transfer case on some 1986 K30 models, equipped with a 4 speed manual transmission. This condition may be caused by an improperly machined transfer case adapter. The bore of the adapter at the transfer case end should be machined to a depth of 25 mm.

Units that develop a leak at this area may have an adapter bore machined to only 14 mm which does not seat properly against the transfer case. To correct this condition, adapters that have been improperly machined must be replaced.

VEHICLES INVOLVED

Involved are certain 1986 Chevrolet K30 Light Duty Model Trucks equipped with 4 speed manual transmission (RPO M20) built within the following Vehicle Identification Number (VIN) breakpoints:

PLANT FROM THROUGH ----- ---- ------- Janesville GJI58955 GJI67154

St. Louis GS170448 GS176924

Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Iden- tification Number, owner name and address data, and are furnished to the involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign.

These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle regis- tration 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. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned.

OWNER NOTIFICATION

Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of Owner Letter included with this bulletin).

DEALER CAMPAIGN RESPONSIBILITY

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.

Whenever a vehicle subject to this campaign is taken into new or used vehicle inventory, or it 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 or releasing the vehicle.

Owners of vehicles recently sold from your new vehicle inventory are to be contacted by the dealer, and arrangements made to make the required correction according to instructions contained in this bulletin.

PARTS INFORMATION

Parts are to be obtained from Service Parts Operations (SPO) (formerly known as GMWDD). To ensure these parts will be obtained as soon as possible, they should be ordered from SPO on a C.I.O. with no special instruction code, but on an advise code (2).

Vehicles determined to have the mis-machined adapter described in the "Service Procedure" section of this bulletin require replacement of the following parts and addition of transmission lubricant as required.

PART QUANTITY NUMBER DESCRIPTION PER VEHICLE ------ ----------- ----------- 15597792 Transfer Case Adapter 1 (as required)

3901180 Gasket (Adapter to 1 (as required) transmission)

15594357 Gasket (Adapter to transfer 1 case)

NPN SAE 80W or SAE 80W-90 4 quarts Gear lubricant

SERVICE PROCEDURE

INSPECTION

- Disconnect the cable at the negative battery terminal.

- Raise and support vehicle on a hoist.

- Remove skid plate if equipped.

- Drain the transmission.

- Disconnect the speedometer cable at the transfer case.

- Separate the front propshaft from the transfer case. Move it away from the work area and secure it.

- Remove the shift lever linkage from the transfer case.

- Support transfer case with a suitable stand and remove bolts attaching it to the transmission adapter. Remove transfer case.

- Measure the depth of the adapter bore. It should be 25 mm, (Figure No. 1). If the bore depth is less than 25 mm replace the adapter. Follow replacement procedure outlined below. If the bore depth is 25 mm reverse the above procedure to reinstall parts. Use a new gasket between the adapter and transfer case.

ADAPTER REPLACEMENT

- Remove the adapter mount bolts from the crossmember. Lift and support the transmission so that the adapter can be removed.

- Remove adapter from vehicle. Transfer mount to new adapter.

- Using a new gasket install adapter to transmission.

- Lower transmission and bolt mount to the crossmember.

- Install transfer case to new adapter using a new gasket.

- Connect transfer case to new adapter using a new gasket.

- Connect transfer case shift linkage and speedometer cable.

- Reinstall rear propshaft assembly.

- Connect front propshaft.

- Reinstall skid plate if removed.

- Fill transmission with SAE-BOW, or SAE-80W-90 CL-5 lubricant, approximately 4.0 quarts.

- Lower vehicle.

- Reconnect battery cable.

TORQUE SPECIFICATIONS:

Adapter to transfer case 33 N.m (24 lb ft) Adapter to transmission 33 N.m (24 lb ft) Adapter mount to crossmember 54 N.m (40 lb ft) Skid plate to crossmember 63 N.m (46 lb ft) Transmission filler plug 23 N.m (17 lb ft) Rear propshaft front flange bolts 100 N.m (74 lb ft) Propshaft to rear axle 33 N.m (24 lb ft) Propshaft center bearing to hanger bracket 33 N.m (24 lb ft) Propshaft to transfer case 15 N.m (11 lb ft)

CAMPAIGN IDENTIFICATION LABEL (Figure 2)

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 five digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or ballpaint 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.

CLAIM INFORMATION

Submit a Product Campaign Claim with the information indicated below:

FAILED PARTS LABOR LAB OTH* NET** REPAIR PERFORMED PC PART NO. ALLOW FC Op HRS HRS AMT ----------------------------------------------------------------------------

INSPECT TRANSFER CASE 1 15594357 ** 00 V3730 1.6 0.1 $15.00 ADAPTER ONLY (W/O SKID PLATE)

INSPECT TRANSFER CASE 1 15594357 ** 00 V3732 1.9 0.1 $15.00 ADAPTER ONLY (WITH SKID PLATE)

INSPECT & REPLACE 3 15597792 ** 00 V3731 2.1 0.1 $15.00 TRANSFER CASE ADAPTER (W/O SKID PLATE)

INSPECT & REPLACE 3 15597792 ** 00 V3733 2.4 0.1 $15.00 TRANSFER CASE ADAPTER (WITH SKID PLATE)

*Campaign Administrative Allowance

**The "Parts Allowance" should be the sum total of the current SPO Dealer Net price plus 30% of all parts required for the repair.

***The (Net Amount) will automatically be given for labor operations V3730, V3731, V3732 and V3733 to cover the cost of tranamission fluid used in conjunction with this correction.

Dealers will automatically receive the correct labor and material allowance based on the labor operation perforned.

Refer to the Chavrolet Claims Processing Manual for details on Product Campaign claim submission.

ADMINISTRATIVE PROCEDURE

REFER TO THE CURRENT CHEVROLET SERVICE POLICIES AND PROCEDURES MANUAL AND CLAIMS PROCESSING MANUAL FOR CAMPAIGN HANDLING AND ADMINISTRATIVE PROCEDURES.

Chevrolet Motor Division GENERAL MOTORS CORPORATION

(Notification Used By Chevrolet motor Division)

Dear Chevrolet Truck Owner:

General Motors has determined that transmission fluid may leak from the transfer case adapter where it meets the transfer case on some 1986 K30 models, equipped with a 4 speed manual transmission. This condition may be caused by an improperly machined transfer case adapter.

To correct this condition if it exists in your vehicle, the adapter will be inspected and replaced if necessary. This service will be performed for you at no charge.

Instructions for this service have been sent to your Chevrolet dealer. Please contact your dealer to arrange a service date. The labor time to inspect vour vehicle is approximately 1 1/2 hours. If the transfer case adapter must be replaced it will take an additional 30 minutes. Please ask vour dealer if you wish to know how much additional time will be needed to process your vehicle.

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 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.

Chevrolet Motor Division GENERAL MOTORS CORPORATION

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.