This factory service and repair manual for the 1991 GMC W5500 Forward documents a single-specification truck. There is one engine, a 6.5L inline-six displacing 396 cubic inches, naturally aspirated and diesel-fueled; one body form, the low tilt straight truck; and one trim code, W5R042. For a fleet running several of these side by side, that uniformity means every torque figure, every specification and every diagnostic sequence in the book applies to all of them without qualification.
Engines covered
- 6.5L inline-six (396 cu in) — naturally aspirated, diesel
Body styles covered
- Straight truck, low tilt
Trims covered
- W5R042
Known issues on the 1991 W5500 Forward. The federal record for the 1991 W5500 Forward is clean: NHTSA lists no recalls for the model year and no owner complaints against it. The manual's job is consequently a routine one, covering the naturally aspirated 6.5L diesel and the chassis and electrical systems around it with step-by-step procedures, published specifications, torque values and full wiring diagrams for troubleshooting.
