This factory service and repair manual for the 2002 GMC W3500 Forward lists no trim ladder at all — the year is covered by the single W3S042 build code — so the meaningful choice is under the cab. Buyers took either the naturally aspirated 5.7L overhead-valve V8, 350 cubic inches on gasoline, or the turbocharged 4.8L inline-four, 290 cubic inches on diesel. The manual is written to that split, holding procedures, specifications, torque values, wiring diagrams and diagnostics for both engines and for the chassis they share.
Engines covered
- 5.7L V8 (350 cu in) — OHV, naturally aspirated, gasoline
- 4.8L inline-four (290 cu in) — turbocharged, diesel
Trims covered
- W3S042
Known issues on the 2002 W3500 Forward. No entry against the 2002 W3500 Forward exists at NHTSA, neither a recall nor an owner complaint. The manual's value here is in the routine: valve, injection and turbocharger specifications on the 4.8L diesel, ignition and fuel-delivery figures on the 5.7L V8, cooling-system service for both, and the brake, axle and steering procedures that a medium-duty truck consumes on a schedule. Torque values are given for the fasteners that matter, and the wiring diagrams cover the charging, starting and lighting circuits along with the sensors feeding engine diagnostics.
