The International Harvester 1066 tractor, produced primarily in the early to mid-1970s, represents a robust and reliable workhorse in the agricultural sector. As part of IH's successful 06 and 66 series, this diesel-powered machine is recognized for its strong construction and dependable performance, delivering approximately 70-90 PTO horsepower with robust torque characteristics suitable for demanding farming applications. Its design emphasizes mechanical and hydraulic systems, featuring a manual synchromesh or optional Power Shift transmission with multiple gears for versatile operation, and wet disc brakes for safety. The IH 1066 is a testament to International Harvester's legacy as a major American manufacturer, built to provide enduring service and efficiency. This official factory service repair manual, presented in English and comprising hundreds of pages, is designed to provide comprehensive guidance for all styles of the IH International Harvester 1066 Tractor. It covers a vast array of systems, including detailed procedures for engine overhaul, lubrication, cooling, fuel, transmission, drivetrain, braking, steering, suspension, bodywork, intake/exhaust, hydraulics, and electrical systems. The manual offers routine maintenance schedules, advanced troubleshooting guides, complete disassembly and reassembly instructions, and specific procedures for component rebuilds. Featuring step-by-step instructions, diagnostic information, and visual aids such as illustrations and diagrams, this manual is an essential resource for tractor owners, mechanics, and technicians seeking to maintain and repair their equipment effectively, saving significant labor costs.