This factory service and repair manual for the 1989 GMC W7500 Forward spans three turbocharged diesel inline-sixes: a 6.5L of 396 cubic inches, an 8.4L of 513 and a 5.8L of 353. All three were fitted to the same low tilt straight truck in the same W7R042 trim, which makes the engine sections the main point of divergence in the book. Their specifications, torque values and diagnostic routines are given individually so no figure is carried across by assumption.
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 1989 W7500 Forward. NHTSA holds nothing against this model year, neither a recall campaign nor a single owner complaint. What remains is the substantive part of the manual, which has three engines to serve, the turbocharged 6.5L, 8.4L and 5.8L inline-sixes, plus the chassis and electrical systems common to all of them, documented with procedures, specifications, torque values, wiring diagrams and diagnostics.
