The United States military has long been obsessed with lightweight, easily transported vehicles. In World War II, it was all about getting them into gliders or transport planes. Then it was parachute capability. When the helicopter went mainstream, the goal was to make them luggable by chopper.
The development of an air-portable extra-light 4x4 started not long after the legendary jeep went into production. On its own, the notable small car maker, Crosley, came up with the “Pup” 4x4 in 1942, and the military liked it enough to make specs for a revised vehicle and sent them out to a number of manufacturers. The 1943 result was prototypes from Chevrolet, Crosley, Kaiser, and Willys. They all weighed between 900 and 1,600 pounds. The Chevrolet was probably the most advanced, followed by the Kaiser, but the Willys Air Cooled (or WAC) survived the tests longer and provided a basis for more development and tests.
In late 1944, Willys debuted the Jungle Burden Carrier (JBC), which incorporated some of the better features of the Chevrolet combined with the platform of the WAC. It had a cast “H-frame” that incorporated a rear transaxle and driveshaft with front and rear portal-style axles. This structural member provided the majority of the structural elements for the JBC with a platform on top. The driver sat in one corner, feet extended out onto a tubular platform. The JBC, patent file 1944, was the clear ancestor of the later M274 Mule. Barney Roos, the chief engineer at Willys, and the guy primarily responsible for the Willys version of the WWII jeep, has his name on the 1944 JBC patent.
The end of WWII also brought an end to the lightweight projects, but when they were revived in the early ’50s, Willys dusted off the JBC design, gave it some fresh technology, and by 1956, their XM274 design had been accepted for production. It was a remarkable vehicle, capable of carrying 110 percent of its curb weight. There was seating for only one, but all of the 96x46.6-inch platform was optionally available for cargo with the operator driving the vehicle as he walked behind or beside it. The “Mule” had a top speed of up to 25 mph and a range of up to 150 miles.
There were six variations of M274. The first two models, the M274 and M274A1, were built by the commercial products division of Willys Motors to the tune of 4,357 units and had a Continental-Willys AO-53 four cylinder air-cooled engine (53ci, 17 hp/30 lb-ft of torque) that was patterned after the legendary VW pancake engine. The AO-53 was backed up by a three-speed manual and a two-speed transfer case. It didn’t have a suspension system, the fat tires at 12 psi serving that purpose. It was four-wheel steer, but the rear steer could be disengaged. The axles were portal-style with a 4.11:1 overall ratio, with 2.2:1 of that from the reduction in the portal.
The M274A2 debuted in 1965 and was built by Bowen-McLaughlin-York into 1967. The major difference in the A2 was a change to the two-cylinder A0-42 engine. It was a Continental/Hercules 42ci engine that made 14 hp. The AO-53 was problematic, with overheating problems in hot weather. The A2 was the most numerous variant, with 3,609 units built. The M274A3 was an M274 with a rebuild that included replacing the A0-53 with an AO-42. The M274A4 was a similar rebuild of the M274A1. In both cases, the units received upgrades to the latest and greatest parts. The final variant was the M274A5 built starting in 1965 and finishing off in 1970. These were a major upgrade that eliminated the magnesium alloy platform, replacing it with an aluminum piece. Of the 3,240 A5 models built, 875 were built with two-wheel steering. A total of 11,240 Mules were built of all types
Besides schlepping cargo, the Mule could even mount weapons systems. The most powerful system commonly seen was the M40 106mm recoilless rifle, and it was extensively used in Vietnam and later. When the TOW (Tube-launched, Optically-tracked, Wire-guided) missile went into service in 1970, a mount was designed for the Mule and so equipped, it’s most common purpose in later years was with Airborne units, or the Marines, as a missile carrier. Reportedly there were mounting systems for the 7.62mm M60 machine gun and .50 cal M2.
Mules saw extensive use in Vietnam, and most of the approximately 5,000 units lost in service died there or were left to the South Vietnamese Army when the United States left. The Mule’s role in military doctrine gradually faded starting in the mid-’70s and, by the early ’80s, had been largely withdrawn from service. The early models hit the surplus market in the late ’60s, with the last ones sold off in the late ’80s.
This Mule belongs to Tom Price, whose experience as a Marine in the ’60s led him to collect everything that caught his fancy, from Mules to LVT Alligators (Landing Vehicle Tracked), as long as it was once Marine Corps issue. Stay tuned to see more from his extensive collection.