Factory service manual.  Covers NRR, NQR, NPR diesel trucks.  Includes GM & Chevrolet versions.

Covers:

1. General info, maintenance & lubrication
2. Heating & AC system
3. Frame, cab & sheet metal
4. Steering, suspension, front axle, alignment, wheels & tires
5. Rear axle & propeller shaft
6. Brakes
7. Engine, including fuel system, fuel injection, cooling & engine electrical
8. Transmission & clutch
9. Electrical system including wire diagrams
10. Cab