The Allis-Chalmers WD Agricultural Tractor, produced from 1948 to 1953, represents a significant piece of American agricultural machinery. Designed for the North American market, this tractor is powered by an Allis-Chalmers gasoline, 4-cylinder, valve-in-head engine with a displacement of 149.0 cubic inches. It features a 4-speed manual transmission and a single dry plate clutch, embodying the robust engineering characteristic of its era. The WD is recognized for its work capability and reliability, making it a valuable asset for farming operations and a notable model in the Allis-Chalmers lineage, succeeding the WC and preceding the WD45. This comprehensive Service Repair Manual provides detailed information for the Allis-Chalmers WD tractor. It covers essential systems including the engine, fuel, cooling, electrical, chassis, transmission, hydraulic, and power take-off systems. The manual includes procedures for periodic maintenance, troubleshooting, engine rebuilding, component replacement, and adjustments. With detailed, step-by-step instructions, hundreds of photos and illustrations, and diagnostic capabilities, this manual is an indispensable resource for owners and professional mechanics alike, enabling effective maintenance, repair, and restoration to ensure optimal function and longevity.