1988 GMC General Service and Repair Manual
This factory service and repair manual for the 1988 GMC General carries a long engine list, with eight diesels: the 7.0L inline-six, the 9.0L V6, the 12.1L V8, the turbocharged 10.0L, 14.0L and 14.6L inline-sixes and the turbocharged, aftercooled 11.1L and 12.7L inline-sixes. Bodies run to straight trucks in long, medium and low tilt conventional form and tractors in medium and long conventional form, across six build codes. Whatever build code is on the work order, the manual answers system by system with procedures, specifications, torque values, wiring diagrams and diagnostics.
Engines covered
- 14.0L inline-six (855 cu in) — turbocharged, diesel
- 11.1L inline-six (677 cu in) — turbocharged, aftercooled, diesel
- 14.6L inline-six (893 cu in) — turbocharged, diesel
- 9.0L V6 (552 cu in) — diesel
- 12.7L inline-six (774 cu in) — turbocharged, aftercooled, diesel
- 12.1L V8 (736 cu in) — diesel
- 10.0L inline-six (611 cu in) — turbocharged, diesel
- 7.0L inline-six (426 cu in) — diesel
Body styles covered
- Straight truck, long conventional
- Straight truck, medium conventional
- Tractor truck, medium conventional
- Straight truck, low tilt
- Tractor truck, long conventional
Trims covered
- N9E020 Gliders - Medium Conventional
- N9E042
- N9E064
- N9F020 Gliders - Long Conventional
- N9F042
- N9F064
Known issues on the 1988 General. The federal record for the 1988 General is clean, showing no recalls and no owner complaints at NHTSA. That puts the emphasis where it belongs on a truck like this, which is on the service data for eight diesels, from the 7.0L inline-six to the turbocharged, aftercooled 11.1L and 12.7L inline-sixes. Each has its specifications and procedures, and around them sit the chassis and driveline torque values, the cab and lighting wiring diagrams, and the diagnostics for every system documented.
THE REAR AXLE RELAY VALVES (ONE PER AXLE) MAY NOT MEET BRAKE RELEASE TIMING REQUIREMENTS OF FMVSS 121.
THE REAR AXLE BRAKES MAY NOT RELEASE IN THE TIMESSPECIFIED BY FMVSS 121.
REPLACE THE NONCOMPLYING RELAY VALVES.
