In the late 1970s the M809 series 5-ton (4,536 kg) 6x6 trucks, based on a 1949 design, were becoming old and mechanically dated. It was still a useful type, with 35,000 in service. A "Product Improveme… See more

All models of the M939 share a common basic chassis, cab, hood, and fenders. The basic truck is a 6×6 (three axles, six wheels, all of which are powered) heavy truck. Early M939s were rebuilds of M809 vehicle chassis wit… See more

The M923 (M925 w/winch) was the standard cargo version of the series. It had a 14 by 7 feet (4.3 m × 2.1 m) body with drop sides so it could be loaded from the side by forklifts. It had a bottom hinged tailgate. Si… See more

The safety of the M939 series of trucks has been criticized, especially braking performance and stability when loaded. In 1999 the U.S. Army began retrofitting anti-lock brake systems to the M939 trucks. Until the trucks … See more