This factory service and repair manual for the 1991 GMC C3500HD covers a single configuration — a two-door conventional cab and chassis in Base trim — which is exactly what a truck built to be finished by someone else usually is. Three engines are listed: the 7.4L and 5.7L naturally aspirated gasoline V8s and the 6.2L diesel V8. With one body and one trim, the coverage concentrates on mechanical work, and the procedures, specifications, torque values, wiring diagrams and diagnostics run system by system through the chassis.
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 cab & chassis, conventional
Trims covered
- Base
Known issues on the 1991 C3500HD. Two recalls appear on the federal record. One concerns replacement oil filters that may not seal properly and can let engine oil escape toward a fire risk; the other describes heat inside the automatic transmission forcing fluid out of the vent tube where it can ignite. Two owner complaints are logged with NHTSA, one on the tires and one on the service brakes. All of that lands in sections the manual covers closely — lubrication specifications, transmission service and cooling, and brake repair with its adjustment procedures and torque values.
