M-939 Series 5-ton, 6x6 Trucks

The M939 truck was introduced in 1983, a Product Improvement Package upgrade of the M-809 series of 5-ton, 6x6 trucks. The M939s are general-purpose military vehicles, primarily designed for tactical, off-road use, with a top speed of 65 mph. The older fleet of M809 series tactical trucks were augmented by the M939 series without replacement.

M923 Truck, Cargo, 5-ton, 6x6, 6x6 Dropside, on a Somali road, between Mogadishu and Biadoa, Operation Restore Hope, 14 January 1993
M923 Truck, Cargo, 5-ton, 6x6, 6x6 Dropside, with machinegun ring mount, on a Somali road, between Mogadishu and Biadoa, Operation Restore Hope, 14 January 1993.

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US Military M-939 Series 5-ton, 6x6 Trucks

The M-939 Series 5-ton, 6x6 truck design was created by AM General Corp. who also built the M939 and M939A1 trucks. The M939A2 trucks, delivered starting in 1989, were produced by Bowen-McLaughlin-York.

The major improvements of the M939 Series vehicles over the M809 Series vehicles are as follows:

  • Allison automatic transmission
  • Improved power steering system
  • Complete air brake system
  • Improved cooling system
  • Improved electrical system
  • Cab for three crew members
  • Tilt hood
  • Hydraulically powered front winch
  • STE/ICE engine diagnostic system

The Family of Medium Tactical Vehicles (FMTV) will eventually replace the M939 series vehicles, along with the M809 series and other legacy vehicles, as resources permit.

SGT Gregory D'Angelo, 268th Transportation Co., checks the engine of an M-923 5-Ton Cargo Truck, Antigua, 19 April 2002
SGT Gregory D'Angelo, 268th Transportation Co., checks the engine of an M-923 5-Ton Cargo Truck, Antigua, 19 April 2002.

M-939 Series 5-ton, 6x6 Trucks Models and Variants

There are many variants of the M939 series 5-ton 6x6 trucks including:

  • M923 Truck, Cargo: 5-ton, 6x6 Dropside
    • M923 NSN 2320-01-050-2084
    • M923A1 NSN 2320-01-206-4087
    • M923A2 NSN 2320-01-230-0307
  • M924 Truck, Cargo, 5 ton, 6x6 LWB w/o winch NSN 2320-01-047-8773
  • M925 Truck, Cargo: 5-ton, 6x6 Dropside w/winch
    • M925 NSN 2320-01-047-8769
    • M925A1 NSN 2320-01-206-4088
    • M925A2 NSN 2320-01-230-0308
  • M927 Truck, Cargo: 5-ton, 6x6 XLWB
    • M927 NSN 2320-01-047-8771
    • M927A1 NSN 2320-01-206-4089
    • M927A2 NSN 2320-01-230-0309
  • M928 Truck, Cargo: 5-ton, 6x6 XLWB w/winch
    • M928 NSN 2320-01-047-8770
    • M928A1 NSN 2320-01-206-4090
    • M928A2 NSN 2320-01-230-0310
  • M929 Truck, Dump: 5-ton, 6x6
    • M929 NSN 2320-01-047-8756
    • M929A1 NSN 2320-01-206-4079
    • M929A2 NSN 2320-01-230-0305
  • M930 Truck, Dump: 5-ton, 6x6 w/winch
    • M930 NSN 2320-01-047-8755
    • M930A1 NSN 2320-01-206-4080
    • M930A2 NSN 2320-01-230-0306
  • M931 Truck, Tractor: 5-ton, 6x6
    • M931 NSN 2320-01-047-8753
    • M931A1 NSN 2320-01-206-4077
    • M931A2 NSN 2320-01-230-0302
  • M932 Truck, Tractor: 5-ton, 6x6 w/winch
    • M932 NSN 2320-01-047-8752
    • M932A1 NSN 2320-01-205-2684
    • M932A2 NSN 2320-01-230-0303
  • M933 Truck, Tractor: 5-ton, 6x6 w/winch
    • M933 NSN 2320-01-047-8768
    • M933A1 NSN
    • M933A2 NSN
  • M934 Truck, Van, Expansible: 5-ton, 6x6, XLWB
    • M934 NSN 2320-01-047-8750
    • M934A1 NSN 2320-01-205-2682
    • M934A2 NSN 2320-01-230-0300
  • M935 Truck, Van, Expansible: 5-ton, 6x6, XLWB w/Hydraulic Lift Gate
    • M935 NSN 2320-01-047-8751
    • M935A1 NSN 2320-01-205-2683
    • M935A2 NSN 2320-01-230-0301
  • M936 Truck, Medium Wrecker: 5-ton, 6x6 w/winch
    • M936 NSN 2320-01-047-8754
    • M936A1 NSN 2320-01-206-4078
    • M936A2 NSN 2320-01-230-0304
  • M939 Truck, Chassis: 5-ton, 6x6 w/winch
    • M939 NSN 2320-01-048-2450
    • M936A1 NSN
    • M936A2 NSN
  • M940 Truck, Chassis: 5-ton, 6x6 w/winch
    • M940 NSN 2320-01-047-8743
    • M940A1 NSN
    • M940A2 NSN
  • M941 Truck, Chassis: 5-ton, 6x6
    • M941 NSN 2320-01-048-8742
    • M941A1 NSN
    • M941A2 NSN
  • M944 Truck, Chassis, 5-ton, 6x6
    • M944 NSN 2320-01-047-8745
    • M944A1 NSN 2320-01-205-2667
    • M944A2 NSN 2320-01-230-0287
  • M945 Truck, Chassis, 5-ton, 6x6
    • M945 NSN 2320-01-050-4894
    • M945A1 NSN 2320-01-205-2668
    • M945A2 NSN 2330-01-230-3261

Over 30,000 of the M939 series trucks were delivered to the U.S. military. Of the many models in the M-939 series of 5-ton, 6x6 trucks, the most common in service were:

  • M923 Truck, Cargo
  • M925 Cargo Truck w/Winch
  • M927 XLWB Truck
  • M931 5-ton Tractor
  • M936 Medium Wrecker.

Wheelbase:

  • M927, M928, M934, and M945 model vehicles utilize the 215 in. (546.1 cm) Extra Long Wheelbase (XLWB) chassis to facilitate transporting of large and awkward loads
  • M923, M925, and M936 model vehicles utilize the 179 in. (454.7 cm) wheelbase
  • M929, M930, M931, and M932 model vehicles utilize the 167 in. (424.2 cm) wheelbase

Engines used for the M939 series were:

  M939 & M939A1 M939A2
Engine Model 655cid Cummins NHC 250 504.5cid Cummins 6CTA8.3
Fuel Diesel Diesel
Horsepower 240@2100rpm 240@2100rpm
Torque 685 lb-ft@1500rpm 745 lb-ft@1500rpm
NSN 2815-01-111-2262 2815-01-312-0018

The M939 was fitted with 11:00R20 tires and tandem wheels on the rear axles while the M939A1 and M939A2 trucks were fitted with single rear wheels and larger 14:00R20 tires. Only the M939A2 vehicles are equipped with the centralized tire inflation system (CTIS).

The air brakes of the M939 series trucks are overly sensitive when the trucks are lightly loaded, empty, or when operating the vehicle on wet or slippery pavement. To rectify this problem, the military retrofitted these trucks with ABS brakes between 1999-2002.

Manuals for the M-939 series of 5-ton 6x6 trucks will be numbered TM 9-2320-272-xx where the xx represents the maintenance level. All together there are dozens of multi-volume manuals for the series of trucks.

Find additional photos and hi-res versions of the M939 series 5-ton 6x6 Trucks at the Olive-Drab Military Mashup:

Marines from the Battalion Landing Team 1/1 Weapons Company, Camp Pendleton refresh at the 400-gallon M149A1 Water Buffalo trailer after completing the Supporting Arms Coordination Exercise (SACEX) portion of Exercise KERNEL BLITZ 97 at Marine Corps Air Ground Combat Center (MCAGCC), Twentynine Palms, CA, 27 June 1997. The trailer is towed by an M939-series 5-ton 6x6 truck.
Two Marines with 24th Marine Expeditionary Unit (24th MEU) stand by beside the M-2 .50-caliber machine gun mounted on the roof of an M-939 5-ton cargo truck as two other Marines attempt to repair a second M-939 that broke down while traveling through the city, 28 Apr 1991.
HMMWV is discharged from the S.S. Equality State during an Army and Navy joint logistics-over-the-shore (JLOTS) exercise conducted off the coast of Puerto Rico in summer, 2009. Performing JLOTS is necessary when deep-water ports are not available or sufficiently equipped to offload equipment in port.  In the exercise, 115 heavy trucks and high-mobility, multipurpose, wheeled vehicles (HMMWVs) were moved from the shore to the ship and back ashore.  M939 series 5-ton truck is to the right.
Marine Service Support Group 24 Marines in an M-939 series 5-ton 6x6 cargo truck, part of a convoy entering Zakhu, Northern Iraq during Operation Provide Comfort, 26 April 1991
An M-939 series 5-ton cargo truck, part of a 32-vehicle convoy for a communications unit, passes through a gate at Aviano Air Base, Italy, after a four-day trip from Sembach Air Base, Germany, 11 April 1993. The unit is deploying to Aviano in support of Operation Deny Flight, the enforcement of the United Nations-sanctioned no-fly zone over Bosnia and Herzegovina.
Experimental M939 series gun truck leaving Camp Anaconda, Balad, for its first convoy escort mission with the U. S. Army 7th Transportation Battalion, 17 July 2004.  With funding from the Defense Advanced Research Projects Agency (DARPA) and in collaboration with the U.S. Army, gun truck armor kits for M939, FMTV, and MTVR were deployed to provide convoy protection for American troops on the roads of Iraq.

Recommended Book with more About the M939 Series of 5-Ton 6x6 Trucks