The Allis Chalmers Big Ten is a compact utility tractor, likely produced during the 1960s and 1970s, representing a robust and reliable piece of agricultural machinery. Known for its durable design and practical functionality, this tractor was engineered for a variety of tasks on small farms, gardens, and for general property maintenance. Its heritage is rooted in the strong reputation of Allis Chalmers as a leading American manufacturer of agricultural equipment, a brand recognized for innovation and longevity. The Big Ten, with its estimated 10-15 PTO horsepower, typically powered by a 2-cylinder gasoline engine, offers essential performance for its intended applications. This comprehensive workshop service repair manual provides an in-depth resource for the maintenance and repair of the Allis Chalmers Big Ten tractor. Covering a wide array of systems including the engine, fuel, transmission, clutch, drive axles, steering, brakes, electrical, hydraulic, and power take-off (PTO), this manual is essential for ensuring optimal performance and longevity. It details routine maintenance procedures, systematic troubleshooting guides, step-by-step repair and overhaul instructions for major components, and critical adjustment procedures. Technical specifications, fluid recommendations, and common issue diagnostics are also included, making it an invaluable tool for owners, mechanics, and technicians alike.