The International Harvester 986 is a heavy-duty agricultural tractor, produced approximately between 1976 and 1981. Renowned as a robust and reliable workhorse, this model was part of IH's successful '86 Series, known for advancements in power and operator comfort. It features a powerful 466 cubic inch (7.6 Liter) inline 6-cylinder diesel engine, often turbocharged, delivering approximately 110-125 PTO horsepower. The tractor is equipped with a manual transmission featuring a 16-speed PowerShift and a dual-clutch system, designed for efficient operation across various field tasks. Its engineering prioritizes functionality and durability, making it a respected machine in the agricultural community. This Workshop Service Manual (WSM) provides comprehensive coverage for the International Harvester 986 tractor, detailing all routine maintenance and repair jobs. It offers in-depth information on engine diagnostics and rebuilds, fuel, cooling, lubrication, ignition, transmission, power take-off, hydraulic, steering, brake, electrical, chassis, axles, and operator station systems. The manual includes step-by-step instructions, troubleshooting guides, diagnostic charts, and detailed diagrams, empowering owners and technicians to maintain and repair the vehicle effectively. Its purpose is to facilitate cost-effective upkeep and ensure the longevity and optimal performance of the tractor.