This factory service and repair manual for the 2006 GMC W3500 Forward is written around the pairing of a 364-cubic-inch 6.0L V8 — overhead-valve, naturally aspirated, gasoline — with a turbocharged 5.2L inline-four diesel of 317 cubic inches. One build code, W3S042, covers the model year. Coverage is organized by system: engine mechanical and management, fuel and exhaust, cooling, driveline, brakes, steering, suspension, cab and body, each with its own procedures, specifications, torque values, wiring diagrams and diagnostics.
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 2006 W3500 Forward. Three recalls sit on the federal record for the 2006 W3500 Forward. One concerns fuel tanks that can corrode through and leak, with the fire risk that implies near an ignition source. A second covers diesel trucks where fuel seeps from the pipe at the upper or lower port on the supply pump. The third traces to oil pipe bolts left under-tightened in production, which can loosen with use and let oil escape past the packing seals until the engine seizes and the truck slows abruptly. One owner complaint is recorded. Fuel storage, fuel supply and engine lubrication all have procedures, torque values and diagnostics here.
