2008 GMC T8500 Service and Repair Manual

By 2008 GM's medium-duty business was in its final stretch, and the GMC T8500 carried on unchanged in its two chassis configurations, T8F042 and T8F064, each a straight truck with a low tilt cab. Both use the turbocharged 7.8L inline-six diesel of 475 cubic inches, the engine GM sourced from Isuzu, and both are mechanical twins of the Chevrolet T8500. This factory service and repair manual addresses the 2008 truck directly, with procedures, specifications, torque values, wiring diagrams, diagnostics and maintenance schedules for the engine, driveline, air brakes, chassis and cab.

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 2008 T8500. No recalls are on federal record for this model year, and NHTSA holds no owner complaints. The air brake, engine and driveline procedures in this manual, with their specifications and torque values, carry the routine and preventive work that keeps a truck like this in service.