This comprehensive service repair manual provides detailed instructions and guidance for maintaining and repairing the M939 Series of 5-ton trucks. This manual covers a wide range of models, including cargo trucks (M923, M924, M925, M926, M927, M928), dump trucks (M929, M930), tractor trucks (M931, M932), and van trucks (M934, M935). It also covers the M936 medium wrecker. The manual includes detailed instructions for preventive maintenance checks and services, troubleshooting mechanical and electrical systems, engine and electrical system maintenance, transmission service, and maintenance of propeller shafts, axles, and suspension systems. Numerous illustrations and exploded diagrams enhance the clarity of maintenance procedures, making it easy to understand and follow the instructions. You’ll find comprehensive coverage of the entire vehicle, from the engine and transmission to the electrical system and bodywork. The manual is a vital resource for anyone involved in maintaining or repairing these trucks, including mechanics, technicians, and military personnel.

The M939 series of trucks, also known as the "Heavy Expanded Mobility Tactical Truck (HEMTT)" family, was a groundbreaking development in military logistics during the latter half of the 20th century. Developed by AM General and later manufactured by BMY, the M939 series served as the backbone of US military transport, providing a robust and versatile platform for a wide range of applications. The 5-ton truck variant, characterized by its powerful diesel engine and rugged design, was particularly crucial for hauling vital supplies and equipment in challenging terrain and operational environments. This model embodied the core principles of military vehicle design: reliability, durability, and adaptability, ensuring its effectiveness across diverse missions and theatres of operation.

The M939 series showcased advanced engineering for its time, featuring a robust frame, independent suspension, and a powerful diesel engine that provided sufficient power for off-road mobility and heavy-duty hauling. The trucks were equipped with a range of specialized bodies, including cargo beds, fuel tankers, wrecker units, and even mobile repair shops. These truck variants were designed to meet the specific demands of the battlefield, providing flexibility for a diverse range of logistical tasks. The M939 series proved their worth in various conflicts, including the Gulf War and the wars in Afghanistan and Iraq, demonstrating their reliability and resilience in demanding environments. However, with the advent of newer, lighter, and more advanced trucks, the M939 series has been gradually phased out of frontline service, although many remain in use with reserve units and allied forces. This service repair manual provides essential information for those continuing to maintain and operate these important vehicles.