This factory service and repair manual for the 1988 GMC W5500 Forward is built around a single powertrain: the 6.5L inline-six, 396 cubic inches, naturally aspirated and running on diesel. The truck itself is cataloged in one configuration, a low tilt straight truck, and under one trim code, W5S042. That narrow scope is an advantage on the shop floor, because nothing has to be filtered out by engine or by trim first, and the procedures, specifications and torque values on any given page apply to the truck in front of you.
Engines covered
- 6.5L inline-six (396 cu in) — naturally aspirated, diesel
Body styles covered
- Straight truck, low tilt
Trims covered
- W5S042
Known issues on the 1988 W5500 Forward. No recalls stand against the 1988 W5500 Forward on the federal record, and no owner complaints have been logged with NHTSA for it. What the book is left to do is ordinary maintenance and repair work on the naturally aspirated 6.5L inline-six and the chassis it sits in, with diagnostics, wiring diagrams, torque values and service specifications organized by system rather than by symptom.
