M939 Truck

The M939 Truck is a 5-ton 6×6 U.S. military heavy truck. Designed in the late 1970s to replace the M39 and M809 series of trucks, it has been in service ever since. The M939 evolved into its own family of cargo trucks, prime movers, and recovery vehicles, with about 32,000 in all produced.

Specifications

All models of the M939 share a common basic chassis, cab, and hood/fenders. The basic truck is a 6×6 (three axles, six wheels, all of which are powered) medium truck. Early M939s were rebuilds of M809 vehicle chassis by AM General, with a new automatic transmission, cab, and hood/fender. Suffix –A2 are new production by Bowen-McLaughlin-York/BMY with later model Cummins engine. The vehicles have a wide variety of configurations and weights.

Note that the motor and tire specifications, along with other improvements, apply to the A2 versions (and A1 versions) of each base model listed below. There is an M928, an M928A1, and M928A2.

Engine

The M939 and M939A1 models use a Cummins NHC 250, a 855 cu in (14.0 L) naturally aspirated inline 6 cylinder diesel engine developing 240 hp (180 kW) at 2100 rpm and 685 lbf·ft (929 N·m) of torque at 1,500 rpm. This was the standard engine of the M809 series. The M939A2 models use a newer and smaller Cummins 6CTA8.3 504 cu in (8.3 L) turbocharged inline 6 cylinder diesel engine developing 240 hp (180 kW) at 2100 rpm and 745 lbf·ft (1,010 N·m) torque at 1,500 rpm.