The Allis-Chalmers D-15 tractor, produced approximately between 1959 and 1964, represents a robust and versatile workhorse in the mid-horsepower category. Designed for a wide array of agricultural and industrial tasks, this model embodies the innovation and quality for which Allis-Chalmers was known. Key features include its strong construction, reliable engine options (available in both gasoline and diesel variants), and the optional Power Director transmission, which significantly enhances shifting capabilities. The D-15 was engineered to be a dependable machine, offering a comfortable operator station and solid performance for its intended applications, solidifying its reputation as a valuable asset in its era. This comprehensive Factory Service Repair Manual provides essential information for the maintenance, repair, and troubleshooting of the Allis-Chalmers D-15 tractor. It covers all major systems, including the engine, transmission, hydraulics, electrical system, steering, and braking. Detailed procedures for routine maintenance, component disassembly and reassembly, diagnostic testing, and complete overhauls are included. With clear instructions, torque specifications, and technical data, this manual is an indispensable resource for owners, mechanics, and technicians seeking to preserve the operational integrity and longevity of their D-15 tractor.