This factory service and repair manual for the 1995 GMC W3500 Forward is written around a two-engine lineup that pulls in opposite directions: a turbocharged 3.9L inline-four diesel of 236 cubic inches, and a naturally aspirated 5.7L overhead-valve V8 of 350 cubic inches running on gasoline. One build code, W3S042, is listed for the year, so the split that matters in the shop is fuel type rather than trim. Procedures, specifications, torque values, wiring diagrams and diagnostics are laid out system by system for both.
Engines covered
- 3.9L inline-four (236 cu in) — turbocharged, diesel
- 5.7L V8 (350 cu in) — OHV, naturally aspirated, gasoline
Trims covered
- W3S042
Known issues on the 1995 W3500 Forward. Neither a recall nor an owner complaint appears on the federal record for this model year at NHTSA. What is left is the ordinary work of keeping a cabover in service, and the manual covers it for both powerplants — injection and glow-plug diagnostics with turbocharger and boost specifications on the 3.9L diesel, fuel and ignition figures on the 5.7L gasoline V8, along with torque values for the chassis and driveline and wiring diagrams for the cab, charging and lighting circuits.
