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.
^ Remove the rear propshaft assembly from the vehicle.
^ Support transfer case with a suitable stand and remove bolts attaching it to the transmission adapter. Remove transfer case.
Figure No. 1 - Measure depth of adaptor bore.:
^ 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. Discard old 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-80W, or SAE-80W- 90 GL-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 33N-m. (24 lb.ft.)
Propshaft to transfer case 15 N.m (11 lb.ft.)
PARTS INFORMATION
Parts are to be obtained from General Motors Service Parts Operation (GMSPO). To ensure that these parts will be, obtained as soon as possible, they should be ordered from GMSPO on a C.I.O. order with no special instruction code but order 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 1 (as required)
(Adapter to transmission)
15594357 Gasket 1
(Adapter to transfer case)
NPN SAE-80W or SAE- 4 quarts
80W-90 Gear lubricant
Transmission lubricant is considered as dealer material and is entered in the net amount column on the warranty claim.
WARRANTY INFORMATION
Dealers should submit a warranty claim on each vehicle completed under this campaign.
Labor
Operation
Description *Time **Parts Trouble
Number Allow Allow Code
V3730 Inspect 1.6 hrs. $15.00 96
transfer case adapter only
V3731 Inspect & 2.1 hrs. $15.00 96
replace transfer case adapter
With skid .3 hrs.
plate add
*Add 0.1 hr. to receive administration time allowance.
**This amount is to be entered as a net item to pay for the NPN SAE80 or 90, gear lubricant, required to refill the transmission.
CAMPAIGN IDENTIFICATION LABEL
Each vehicle corrected in accordance with the instructions outlines 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 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" #SD8519
GMC Truck Operation Truck & Bus Group General Motors Corporation 31 Judson Street Pontiac, Michigan 48058
Dear GMC 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 K35 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 GMC Truck dealer. Please contact your dealer to arrange a service date. The labor time to inspect your vehicle in approximately 1-1/2 hours. If the transfer case adapter must be replaced it will take an additional 30 minutes. Please ask your 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 them in making the 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.
GMC TRUCK GENERAL MOTORS CORPORATION