This factory service and repair manual for the 2008 GMC W3500 Forward lists two engines against one build code, W3S042. The gasoline truck runs a naturally aspirated 6.0L overhead-valve V8 displacing 364 cubic inches; the diesel runs a turbocharged 5.2L inline-four of 317. Everything from the clutch back is common, so the manual's structure follows the truck rather than the order sheet — engine chapters where the two differ, and one set of chassis, cab and electrical chapters with procedures, specifications, torque values, wiring diagrams and diagnostics for both.
Engines covered
- 6.0L V8 (364 cu in) — OHV, naturally aspirated, gasoline
- 5.2L inline-four (317 cu in) — turbocharged, diesel
Trims covered
- W3S042
Known issues on the 2008 W3500 Forward. Three recalls sit on this truck's federal record, each naming a different system. Gasoline versions can have the throttle pedal wedge under its steel stopper bolt and hold wide open, so the truck will not slow when the driver lifts. Corrosion is the second problem: the fuel tank rusts until it leaks, and leaking fuel near an ignition source can start a fire. Third, propeller shafts that received too little heat treatment may break in service, stalling the truck or costing the driver control. One owner complaint is logged, against the service brakes. Throttle linkage, fuel storage, driveline and brake procedures are all documented here.
