1988 GMC C3500 Service and Repair Manual
This factory service and repair manual for the 1988 GMC C3500 covers a truck offered as a standard cab pickup, an extended cab pickup or a two-door cab and chassis, in Sierra, Sierra SLE and Sierra SLX trim. Three engines are listed: the 7.4L and 5.7L naturally aspirated gasoline V8s and the 6.2L diesel V8, all overhead-valve. The diesel carries its own specifications throughout, while the chassis, brake, steering, suspension, body and electrical sections apply to every version, each with torque values, wiring diagrams and diagnostics.
Engines covered
- 7.4L V8 (454 cu in) — OHV, naturally aspirated, gasoline
- 6.2L V8 (379 cu in) — OHV, naturally aspirated, diesel
- 5.7L V8 (350 cu in) — OHV, naturally aspirated, gasoline
Body styles covered
- 2-door standard cab pickup
- 2-door extended cab pickup
- 2-door cab & chassis
Trims covered
- Sierra
- Sierra SLE
- Sierra SLX
Known issues on the 1988 C3500. A single recall stands on the federal record, and it describes heat building inside the automatic transmission until fluid is forced out of the vent tube, where it can ignite. One owner complaint is logged with NHTSA, against the service brakes. Both fall inside sections this manual treats at length: transmission service, including fluid level and cooling specifications and the diagnostics for overheating, and the brake system, with hydraulic repair procedures, wear limits, adjustment steps and torque values for the fasteners involved.
UNANTICIPATED HEAT IN THE TRANSMISSION CAN FORCE THE TRANSMISSION FLUID OUT OF THE VENT TUBE.
THE VENTED TRANSMISSION FLUID CAN CATCH FIRE IF EXPOSEDTO A SOURCE OF IGNITION.
INSTALL A LONGER TRANSMISSION VENT HOSE ROUTED TO THE LEFT SIDE OF THE ENGINE COMPARTMENT OF THE VEH
WHILE DRIVING AT 45 MPH AND APPLYING BRAKES, BRAKES WENT STRAIGHT TO THE FLOORBOARD, AND CONSUMER LOST ALL POWER STEERING AND BRAKES. *AK
