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1965 Willys M-274A4 Mule - Jeep Encyclopedia

Posted in Features on March 30, 2015
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In studying Jeep history you will find many odd turns and strange relations but most of them are in some way identifiable as a Jeep. Among those with little apparent Jeep DNA is the M-274 Mechanical Mule, a compact Willys 1⁄2-ton platform vehicle that debuted in 1956.

The Mule story goes back to 1943, when Willys-Overland answered a call for an ultra-light, air-portable 4x4. From that project the WAC (Willys Air-Cooled) was born and tested with several other manufacturer’s designs. By the time 1944 rolled around, the ultra-light project was on the government’s backburner, but the Willys concept, by then called the JBC (Jungle Burdon Carrier), had been developed to a very high degree and a design patent was applied for by Chief Engineer Delmar “Barney” Roos. It was granted in 1948 but languished in a file drawer until 1953. Seeing renewed interest in the idea, Willys-Overland dusted it off, made a new pitch, and by 1956, the XM-274 “Mechanical Mule,” nearly identical to the unit in the 1944 patent, was green-lighted for production as a front-line military rig.

Richard Ross’s M-274A4 is a later rebuild repowered by a two-cylinder AO-42 Continental-Hercules engine making 13hp. The M-274A4s were upgrades of the second generation M-274A1 units built by Willys in the early ‘60s. This one was originally built in 1965. Ross found it as a basket case that had languished for decades. Seating for one plus 1,000 pounds of gear is what this Willys had to offer. The mat is not an original feature but is handy when Ross uses the Mule around his Ohio farm. Moving the steering wheel is only the first part of the process to operate the Mules while walking behind or alongside.

Weighing fewer than 900 pounds, the M-274 was easily helicoptered or dropped by parachute. Its compact size allowed it to operate on narrow jungle tracks, in tight mountainous terrain or other places where the regular jeep was just too big. The Mule was tiny but muscular. It could carry more than its own weight and had four-wheel drive and four-wheel steering. There was seating for only one, but all of the 96x46.6-inch platforms were 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, a range of up to 150 miles, and was even developed into a weapons platform for the 106mm recoilless rifle, the TOW missile, and the .50-caliber machine gun.

The first M-274s used a Willys-built A0-53 four-cylinder air-cooled opposed engine that made 15 hp and 30 lb-ft of torque. The engine was rear mounted under the platform, and power was transmitted by a three-speed manual transmission to a two-speed T-case and into a pair of cast-magnesium alloy portal axles, complete with mechanical lockers. There was no suspension at all, with the 7.50-10 non-directional tires doing that job alone. The M-274 Mules had six generations: the original, plus the M274A1 thru A5. Only the first two generations were built by Willys, and some of the later models were merely rebuilt/updated older units with new designations.

The Hercules flat-two that replaced the original Willys four is a four-stroke engine that makes 13 hp. Most Mules are rope started (oh joy!), but an electric-starting kit was used on some and many have been retrofitted with either the original 24V military kit or a custom-built 12V version. The last-generation M-274A5 Mule also had an electronic starter.

The Mule saw service in Vietnam, but once that conflict ended, many, if not most, were put into storage. Surplus sales started in the ’60s, but the majority of them were sold in the ’80s when the Mule was finally declared totally redundant. Some sources list as many as 11,240 being built, but it’s widely thought some of them were counted twice due to the rebuild programs. Today, Mules are a popular military collectible that still find homes on farms and ranches, where its all-terrain 1,000-pound cargo capacity comes in very handy.

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