This factory service and repair manual for the 1991 GMC W7500 Forward lists three turbocharged diesels, all inline-sixes and all in the same low tilt straight truck under the W7R042 code: the 6.5L of 396 cubic inches, the 8.4L of 513 and the 5.8L of 353. Because the trucks are otherwise identical, the manual's engine chapters carry the differences and the chassis chapters carry what is common, with specifications and torque values quoted accordingly.
Engines covered
- 6.5L inline-six (396 cu in) — turbocharged, diesel
- 8.4L inline-six (513 cu in) — turbocharged, diesel
- 5.8L inline-six (353 cu in) — turbocharged, diesel
Body styles covered
- Straight truck, low tilt
Trims covered
- W7R042
Known issues on the 1991 W7500 Forward. No recalls stand against the 1991 W7500 Forward federally, and no owner complaints have been logged with NHTSA. That leaves the book to be judged on its coverage, which extends to all three turbocharged inline-sixes and the truck they are installed in, with procedures written to the factory sequence, published specifications, torque values, wiring diagrams and diagnostic charts.
