The Allis-Chalmers WD45 tractor, produced from 1953 to 1957, represents a significant advancement over its predecessor, the WD. Featuring a larger 260.5 cubic inch inline 4-cylinder engine, it delivered approximately 45 horsepower at the PTO, offering increased power and improved hydraulics. This robust agricultural machine was designed for versatility and reliability, making it a cornerstone for farming operations of its time. Notable improvements included an optional power steering system, enhancing operator comfort and control. The WD45 is celebrated as an iconic and enduring model in agricultural history. This comprehensive service repair manual provides detailed information for the Allis-Chalmers WD45 tractor. It covers complete engine service, including disassembly, assembly, and overhaul, along with in-depth guidance on the fuel, cooling, electrical, transmission, brake, steering, and hydraulic systems. The manual includes procedures for component removal, installation, repair, and rebuilding, as well as routine maintenance, periodic lubrication schedules, and troubleshooting diagnostics for common issues. It is intended for tractor owners, mechanics, and enthusiasts to facilitate effective maintenance and repair, ensuring the longevity and optimal performance of the vehicle.