This manual covers the International Harvester 966 Tractor, a robust agricultural machine produced from approximately 1971 to 1976. Known for its durability and performance, the 966 is a testament to International Harvester's legacy in agricultural equipment. It typically features a diesel engine, offering substantial horsepower for demanding tasks, and was available with various transmission options, including a 16-speed PowerShift, enhancing its versatility. The 966 is recognized as a workhorse, still valued in the used market for its reliability and straightforward repairability, making it a practical choice for farm owners, mechanics, and enthusiasts. This comprehensive service and repair manual provides detailed information for maintaining and repairing the International Harvester 966 Tractor. It covers essential areas such as engine overhaul, transmission service, brake system repair, electrical system diagnostics, hydraulic system maintenance, and chassis work. The manual includes troubleshooting guides, periodic maintenance schedules, and step-by-step procedures for disassembly and reassembly. Its purpose is to empower owners and technicians with the knowledge needed to ensure the optimal performance, longevity, and safety of the tractor, offering a cost-effective solution for all repair and maintenance needs.