Vehicles, Dealer, Owner and Service
VEHICLES INVOLVEDInvolved are certain 1988 GMC C/K 15-35 Sierra Trucks equipped with 4-speed manual transmission (RPO MM4) built within the following VIN breakpoints:
Model
Year Model Plant From Through
1988 C/K 15-35 Pontiac East SSV JE501630
Fort Wayne SSV JZ500614
Oshawa SSV J1503799
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 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 your new or used vehicle inventory, or it is in your dealership for service in the future, you should take the steps necessary to ensure 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. If no owner's name and address were available to GMC Truck 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 the address listed below in the previously supplied yellow campaign envelopes.
GMC Truck Division General Motors Corporation 101 Union Street Plymouth, Michigan 48170
OWNER NOTIFICATION
Owners will be notified of this campaign on their vehicles by GMC Truck 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
Refer to Service Manual X-8731 Section 4, Propeller Shaft & Axles, and Section 7, Transmission and Clutch for further removal and installation instructions.
4-WHEEL DRIVE
^ Place transfer case in 4H.
^ Disconnect negative battery cable.
^ Unclip and remove shift lever boot from console.
^ Remove shift lever assembly from transmission.
^ Remove console.
^ Lift and support vehicle.
^ Remove transfer case skid plate if equipped.
^ Drain lubricant from transfer case and transmission.
^ Disconnect transfer case shift control linkage.
^ Disconnect wiring harness and vent hose from transfer case.
^ Disconnect front propshaft at transfer case flange.
- Reference mark the relationship of the propshaft at the flange.
^ Remove rear propshaft.
^ Remove transfer case to transmission adapter bolts.
^ Remove transfer case.
^ Disconnect wiring harness from transmission.
^ Remove transmission mount to crossmember nuts.
^ Support and raise transmission with an appropriate jack.
^ Remove crossmember.
^ Remove transmission to clutch housing bolts.
^ Remove transmission and place on a bench.
- Before removing cover assembly from transmission ensure that all forward gears are in neutral and reverse is halfway engaged.
^ Remove and discard transmission cover. Clean case of all gasket material.
Fig. 1:
^ Place new cover assembly halfway in reverse, Figure No. 1, and install new gasket and cover assembly to transmission. Torque bolts 34 N-m (25 ft.lbs.).
^ Reinstall transmission in vehicle. Transmission should be in reverse gear. Torque transmission to clutch housing bolts to 100 N-m (74 ft.lbs.).
^ Reinstall crossmember. Torque mounting bolts to 75 N-m (55 ft.lbs.).
^ Torque transmission mount to crossmember nuts to 47 N-m (35 ft.lbs.).
^ Reconnect wiring harness to transmission.
- Reinstall transfer case to transmission adapter utilizing a new gasket. Torque bolts to 33 N-m (24 ft.lbs.).
^ Reconnect front propshaft. Torque flange bolts to 100 N-m (74 ft.lbs.).
^ Reconnect vent hose and wiring harness to transfer case.
^ Reconnect transfer case linkage.
^ Reinstall skid plate if previously removed.
^ Refill transfer case with Dexron (R) II Automatic Transmission Fluid part number 1051855 (approx. 1.2 quarts).
^ Refill transmission with SAE-80W GL5 or SAE-80W-90 GL5 gear lubricant part number 1052271 (approx. 4.2 quarts).
^ Lower vehicle.
^ Replace console, shift lever assembly, shift lever boot, etc.
^ Reconnect the battery.
2-WHEEL DRIVE
^ Disconnect negative battery cable.
^ Unclip and remove shift lever boot from console.
^ Remove shift lever assembly from transmission.
^ Remove console.
^ Raise and support vehicle.
^ Drain lubricant from transmission.
^ Disconnect wiring harness from transmission.
^ Disconnect propshaft from transmission. Loosen hanger bearing and tie shaft away from work area.
^ Remove transmission mount to crossmember nut.
^ Support transmission.
^ Remove transmission bolts at clutch housing.
^ Remove crossmember.
^ Remove transmission and place on a bench.
- Before removing cover assembly from transmission ensure that all forward gears are in neutral and reverse is halfway engaged.
^ Remove and discard transmission cover. Clean case of all gasket material.
Fig. 1:
^ Place new cover assembly halfway in reverse, Figure No. 1, and install new gasket and cover assembly to transmission. Torque bolts 34 N-m (25 lb..ft).
^ Reinstall transmission in vehicle. Transmission should be in reverse gear. Torque transmission to clutch housing bolts to 100 N-m (74 lb.ft).
^ Reinstall crossmember. Torque mounting bolts to 75 N-m (55 lb.ft).
^ Torque transmission mount to crossmember nut 54 N-m (40 lb.ft.).
^ Reconnect wiring harness.
^ Reconnect propshaft to yoke. Torque bolts to 20 N-m (15 lb.ft). Torque center bearing bracket bolts to 34 N-m (25 lb.ft).
^ Fill transmission with SAE-80W GL5 or SAE-80W-90 GL5 gear lubricant part number 1052271 (approx. 4.2 quarts).
^ Lower vehicle.
^ Replace console, shift lever assembly, shift lever boot, etc.
^ Reconnect the battery.