This factory service and repair manual for the 1989 GMC W5500 Forward addresses a truck sold under one model code, W5R042, in the low tilt straight truck form. Under the cab is the 6.5L inline-six, 396 cubic inches of naturally aspirated diesel, and it is the only engine the book has to account for. Coverage is therefore linear: engine service, chassis systems and the wiring that ties them together, with specifications and torque values quoted for this configuration and no other.
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 1989 W5500 Forward. Federally, the 1989 W5500 Forward has a clean sheet, with no recalls issued against it and no owner complaints appearing in the NHTSA record. That leaves the manual's value in its everyday sections: diagnostic routines for the naturally aspirated 6.5L diesel, torque specifications for engine and chassis fasteners, and wiring diagrams for the electrical circuits on the W5R042 chassis.
