This manual covers the Allis-Chalmers D21 Series 2 tractor, a robust piece of agricultural equipment known for its enduring performance. While specific production years are not detailed, this model represents a significant offering from Allis-Chalmers, a manufacturer with a strong legacy in agricultural and industrial machinery. The D21 Series 2 was engineered for demanding tasks, reflecting the brand's commitment to reliability and functional design, making it a valuable asset for various farming and operational needs. This workshop service manual provides comprehensive guidance for the repair and service of the Allis-Chalmers D21 Series 2 tractor. With 63 pages of detailed information in English, it covers all major systems including the engine, transmission, hydraulics, electrical system, axles, steering, braking, and power take-off. The manual includes step-by-step repair procedures, diagnostic information, adjustment specifications, removal and installation instructions, disassembly and assembly details, lubrication guidelines, and essential safety precautions. It is designed to assist both mechanics and DIY individuals in performing efficient and accurate maintenance and repairs, ensuring the longevity and optimal performance of the tractor.