M931A2 with a Cummins 6CTA8.3 Turbo Engine, Anti-Lock Brakes, 14.00R20 Goodyear Tires, and (CTIS) Central Tire Inflation System which allows for the adjustment of tire pressure with just the push of a button.

The M939 series vehicles are an improved version of the M809 series. The
improvements make M939 series vehicles more reliable and easier to operate. The
major improvements are:

(1) Automatic Transmission
(2) Improved Power Steering System
(3) Complete Air brake System
(4) Improved Cooling System
(5) Improved Electrical System
(6) Three-Crew Member Cab
(7) Tilt Hood

The M931A2 tractor trucks are equipped with a fifth wheel hitch used to haul a semitrailer over a variety of terrain.

The 5-ton load limit rating of M939/A1/A2 series vehicles does not mean
these vehicles are limited to 5-ton payloads. A vehicle rating only indicates the
maximum amount of cargo weight the vehicle axles and frame can withstand when
operating under the worst cross-country conditions.