2008 GMC C4500 Topkick Service and Repair Manual

This factory service and repair manual for the 2008 GMC C4500 Topkick is built around two engines and four chassis configurations. The engines are the turbocharged 6.6L diesel V8 and the naturally aspirated 8.1L gasoline V8; the chassis appears as a conventional two-door cab and chassis, a crew cab and chassis, a cutaway and a cab-and-chassis cutaway, listed under six model codes. Each system — engine, transmission, axles, brakes, steering, suspension, frame, cab and electrical — carries its own procedures, specifications, torque values, wiring diagrams and diagnostics.

Engines covered

• 6.6L V8 (403 cu in) — OHV, turbocharged, diesel
• 8.1L V8 (496 cu in) — OHV, naturally aspirated, gasoline

Body styles covered

• 2-door cab & chassis, conventional
• Cab & chassis, crew cab
• Cutaway
• Cab & chassis, cutaway

Trims covered

• C4C042
• C4C044
• C4E042
• C4E044
• C4U042
• C4V042

Known issues on the 2008 C4500 Topkick. A single recall applies, and it involves equipment added to the truck rather than the truck itself: an aftermarket wheelchair-lift interlock whose protection diode can be knocked out by a voltage spike, leaving the vehicle able to be driven while the lift is deployed. One owner complaint is logged with NHTSA, on the engine and engine cooling. Cooling is a reasonable thing to watch on a medium-duty truck that idles and pulls, and the manual covers the system with coolant routing, thermostat and fan service, temperature specifications and diagnostics.