The 1991 GMC Sierra is a full-size pickup truck built on the robust GMT400 platform, known for its durability and versatility in commercial, work, and personal transportation. This generation represented a significant advancement for GM trucks, featuring a more aerodynamic design and improved ride quality. The Sierra offered a range of capable V6 and V8 gasoline engines, including 4.3L, 5.0L, 5.7L, and 7.4L options, along with a 6.2L diesel engine, providing ample power for hauling and towing. Available in various configurations, including Regular and Extended Cab styles with 6.5 ft and 8 ft bed lengths, the Sierra was engineered to meet diverse user needs, solidifying GMC's reputation for producing reliable and capable vehicles.

This comprehensive service and repair manual provides detailed information for all repairs, covering the 1991 GMC Sierra across all its configurations. It includes in-depth procedures for engine diagnosis and repair, transmission service for both automatic and manual transmissions, drivetrain maintenance, suspension and steering system work, and brake system servicing. The manual also covers the electrical system, HVAC, body repairs, fuel, exhaust, and emissions systems. Furthermore, it details scheduled maintenance, troubleshooting guides, and specific technical specifications, including torque values. This resource is designed to assist owners, mechanics, and technicians in effectively maintaining and repairing the vehicle to professional standards.