The M939 series 5-ton truck represents one of the last great conventional military trucks—a straightforward, mechanically robust workhorse that served American forces for decades and now enjoys a thriving second life in civilian hands. Unlike modern computerized vehicles, the M939 was designed for simplicity and repairability, making it an ideal choice for military vehicle enthusiasts who want something they can actually maintain and use.
Understanding the 5-Ton Designation
The term “5-ton” refers to the truck’s rated payload capacity, not its actual weight. A fully loaded M939 tips the scales at nearly 30,000 pounds. The cargo capacity of 10,000 pounds (5 tons) represents what the truck can safely carry across challenging terrain while maintaining its designed performance envelope.
This rating system dates back to World War II when the Army standardized truck classifications. The 5-ton class occupied the middle ground between lighter 2.5-ton trucks and heavy tractor-trailers, providing an optimal balance of cargo capacity and tactical mobility.
Development History
AM General developed the M939 series in the early 1980s as an upgraded version of the earlier M809 series trucks. The Army wanted improved performance, better parts commonality, and enhanced reliability. The M939 delivered on all counts while maintaining the basic configuration that soldiers knew and understood.
Production ran from 1982 through 1999, with thousands of trucks built for U.S. forces and allied nations. The production run’s length speaks to the design’s success—the Army kept ordering M939s because they worked.
The M939 evolved through several sub-variants, each introducing improvements while maintaining core compatibility:
- M939: Original production trucks
- M939A1: Updated engine and transmission, improved reliability
- M939A2: Final production variant with further refinements
Technical Specifications
The M939’s specifications reveal a truck designed for rugged utility rather than sophistication:
- Configuration: 6×6 (six wheels, all driving)
- Engine: Cummins NHC-250 diesel, 240 horsepower
- Transmission: Allison MT654CR automatic, 5-speed
- Transfer Case: Two-speed with high and low range
- Payload Capacity: 10,000 pounds (5 tons) cross-country
- Towing Capacity: 15,000 pounds
- Gross Vehicle Weight: 29,000 pounds
- Maximum Speed: 55 mph
- Range: 400+ miles
- Fuel Capacity: 76 gallons
- Fording Depth: 30 inches without preparation
The Cummins diesel engine deserves special attention. This powerplant has served in countless civilian applications, meaning parts remain readily available. The engine’s mechanical fuel injection system avoids the complexity of electronic controls, making it repairable in field conditions with basic tools.
The Allison automatic transmission similarly balances capability with simplicity. Automatic operation reduces driver fatigue during long convoy operations, while the transmission’s proven design ensures reliability across varied conditions.
Major Variants
The M939 family includes numerous body configurations built on the common chassis:
M923 Cargo Truck
The basic cargo truck features a 14-foot steel cargo bed with removable side stakes and a canvas cover. Bench seats along the sides can accommodate troops when the truck serves as a personnel carrier. Tie-down rings and stake pockets secure varied cargo configurations.
M925 Cargo with Winch
Identical to the M923 but equipped with a front-mounted 20,000-pound winch. This variant can self-recover from stuck situations or assist other vehicles. Recovery units prefer the winch-equipped trucks for their versatility.
M927 XLWB Cargo
The Extended Long Wheel Base variant stretches the cargo bed to 20 feet, increasing capacity for bulky loads. The longer bed accommodates standard shipping containers and outsized cargo that won’t fit standard trucks.
M931 Tractor
The tractor variant replaces the cargo bed with a fifth wheel for pulling semi-trailers. Common uses include hauling heavy equipment trailers and fuel tankers. The 6×6 drivetrain gives the tractor off-road capability far beyond civilian semi-trucks.
M934 Expansible Van
A specialized variant featuring an expandable shelter body, the M934 serves as mobile command posts, maintenance shops, and communications centers. The shelter sides extend outward to create additional interior space when parked.
M936 Medium Wrecker
The 5-ton wrecker provides recovery capability for medium-weight vehicles. Its crane and winches can right overturned vehicles, pull trucks from ditches, and perform field repairs that would otherwise require evacuation to maintenance facilities.
Operational History
The M939 served in every major American military operation from the 1980s through the 2000s. During Operation Desert Storm, thousands of 5-tons hauled supplies across the Saudi desert and into Iraq and Kuwait. The trucks proved reliable despite harsh conditions that challenged more sophisticated vehicles.
In Somalia, Bosnia, Kosovo, and numerous smaller deployments, M939s provided the unglamorous but essential work of moving supplies where they needed to go. Drivers appreciated the trucks’ predictable handling and ease of maintenance.
Operations Iraqi Freedom and Enduring Freedom marked the M939’s final major combat deployments. By this point, the trucks were showing their age, and the Army began replacing them with newer MTV (Medium Tactical Vehicle) series trucks. Many M939s served out their final years in National Guard and Reserve units before being declared surplus.
Why the M939 is Perfect for Civilian Ownership
Several factors combine to make the M939 one of the most practical military vehicles for civilian use:
Simplicity
No computers, no emissions controls, no complex electronics. The M939 uses mechanical systems throughout. A competent shade-tree mechanic can diagnose and repair most problems with basic tools and common sense.
Parts Availability
The Cummins engine and Allison transmission use components found in civilian trucks and equipment. Rockwell axles appear in numerous commercial applications. Even body-specific parts remain available through surplus channels and aftermarket suppliers.
Reasonable Size
While definitely large, the M939 is more manageable than heavier tactical trucks. It fits in most commercial parking spaces and doesn’t require specialized infrastructure for storage. Many owners keep their trucks at home with minimal accommodation.
Legal Operation
Most M939s can be legally operated with a standard Class A Commercial Driver’s License (CDL). Unlike larger military trucks, they don’t require special permits for most road travel. Registration and insurance, while more expensive than passenger vehicles, remain reasonable.
Practical Utility
The 5-ton cargo capacity actually proves useful. Owners haul equipment, supplies for remote properties, and loads that would overwhelm civilian pickup trucks. The all-wheel-drive system handles conditions that stop ordinary trucks.
Buying a Surplus M939
The surplus market offers steady supply of M939s at various price points. Here’s what buyers should consider:
Condition Assessment
Like any used vehicle, M939s vary dramatically in condition. Some have been meticulously maintained and show minimal wear despite high mileage. Others were driven hard, maintained poorly, and show every mile. Careful inspection before purchase is essential.
Key areas to evaluate include:
- Engine compression and oil pressure
- Transmission shift quality
- Transfer case operation in all ranges
- Differential condition (listen for noise)
- Brake system function and air system integrity
- Frame condition and rust
- Cab rust, especially floor and door frames
- Tire condition and date codes
Pricing
Current market prices for running, operational M939s typically range from $5,000 to $25,000 depending on variant and condition. Wrecker variants command premiums due to their utility. Low-mileage examples or trucks with recent rebuilds may exceed these ranges.
Project trucks—those requiring significant work—can sell for $2,000 to $5,000. These may be viable for mechanically skilled buyers but can quickly consume their purchase savings in parts and labor.
Sources
M939s appear for sale through several channels:
- Government Surplus: GovPlanet, IronPlanet, and direct Defense Logistics Agency sales
- Private Sales: Military vehicle forums, Facebook groups, and classified listings
- Dealers: Specialty military vehicle dealers maintain inventory and can arrange transportation
Common Modifications
Civilian owners frequently modify their M939s for improved comfort and capability:
Power Steering: The original manual steering requires significant effort. Many owners add aftermarket power steering for easier daily operation.
Heater/AC: The original cab heating is minimal, and there’s no factory air conditioning. Aftermarket climate control makes the trucks more comfortable in extreme temperatures.
Seats: Military seats prioritize durability over comfort. Air-ride seats from commercial trucks significantly improve long-distance driving comfort.
Lighting: LED upgrades improve visibility while reducing electrical system load.
Bed Modifications: Owners add stake bodies, flatbeds, dump bodies, and custom boxes for specific applications.
Operating Considerations
Before buying an M939, consider the practical realities of ownership:
Fuel Economy: Expect 6-10 miles per gallon depending on load and conditions. The 76-gallon tank provides reasonable range but expensive fill-ups.
Speed: The governed top speed of 55 mph means highway travel requires patience. Plan extra time for any trip.
Maneuverability: Despite reasonable dimensions, the M939’s long hood and wide turning radius require careful navigation in tight spaces.
Noise: The diesel engine and lack of sound insulation make for a loud cab. Hearing protection is advisable for long trips.
Maintenance: While simpler than modern vehicles, M939s still require regular maintenance. Plan for annual brake checks, fluid changes, and general inspections.
Conclusion
The M939 5-ton truck represents military vehicle ownership at its most practical. These trucks offer real capability, reasonable acquisition and operating costs, and the satisfaction of owning a piece of military history that you can actually use. The design’s emphasis on simplicity and repairability means owners can maintain their trucks without specialized equipment or dealer support.
For those seeking a military truck they can put to work rather than just display, the M939 deserves serious consideration. Thousands remain in civilian hands, supported by an active community of owners who share knowledge and parts sources. Whether you need serious hauling capability, off-road utility, or simply want to experience military vehicle ownership, the 5-ton truck delivers on its reputation as a true workhorse.
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