2007 GMC T8500 Service and Repair Manual

Two chassis configurations return for the 2007 GMC T8500, T8F042 and T8F064, both straight trucks with a low tilt cab and both twins of the Chevrolet T8500. The engine remains the turbocharged 7.8L diesel inline-six of 475 cubic inches, the Isuzu-built six in GM's medium-duty range, and this year's trucks are the ones later called back for air compressor work. This service and repair manual is written to the 2007 build, giving procedures, specifications, torque values, wiring diagrams, diagnostics and maintenance schedules that match the air supply, engine and chassis hardware actually fitted.

Engines covered

• 7.8L inline-six (475 cu in) — turbocharged, diesel

Body styles covered

• straight truck, low tilt

Trims covered

• T8F042
• T8F064

Known issues on the 2007 T8500. Two recalls are on federal record, and both concern the air compressor on trucks with the 7.8L diesel and air brakes: it might not build enough pressure for the brake system, so a stationary truck could stay braked or a moving one could see its spring brakes apply once pressure fell. The 2007 campaign replaced the compressor head, and a 2009 follow-up had dealers test the compressor, removing the suppression valve or replacing the assembly. NHTSA also records one owner complaint, filed against the fuel system and diesel engine. The air supply, brake and fuel system procedures in this manual cover testing and servicing each of these components.