In 1944, Allis Chalmers created a total of 291 vehicles for the U.S. Army Air Corps and the 10th Mountain Division. These vehicles were intended to move supplies through heavy snow and rescue a downed pilot if needed. This vehicle was known as the M7 Snow Tractor, which at just over ten feet long as well as just over five feet wide as well as tall and weighing in at around 2600lbs, was able to traverse snow depths in the 10 foot deep range in temperatures well below zero.
M7 Snow Tractors at one time had a canvas cab which allowed for two passengers, but many later owners, such as Fish & Game Departments that acquired these vehicles post military use, did away with the canvas. Upgrades were necessary for the use others had in mind, and have resulted in all-weather cabs being added to accommodate both more passengers and carry more supplies. Roof racks were also a common modification.
Since these machines were built for a military that wanted Willys Jeep components, they are equipped with a Warner Gear T-84 3-speed transmission. This made for easier maintenance between the different types of vehicles used by the military at the time when it came to both parts and tools. The problem they ran into, and that current owners still run into, is that the T-84 transmission uses brass thrust washers that tend to wear out. When this happens due to the hard work it takes to propel this tractor through snow, gears gain freedom of movement and begin to interfere with one another. This can result in a stranded tractor until new washers can be installed, so to avoid this problem it is best to operate this tractor in high gear/low range even though this equates to slower movement. Another potential problem is snow pack in wet conditions. This happens due to the way the track operates, being tight on top and looser on the bottom. Periodic checks for snow accumulation on a snow tractor are essential to avoid malfunctions or failure of the equipment.
Overall, however, these machines are very effective at the job for which they were intended. They can move through serious snowfall with a surprisingly smooth ride. Since there was such a limited number manufactured (291), acquiring parts can be extremely difficult. Even so, they are highly sought after by collectors and can themselves be difficult to acquire in the first place. If you do manage to find and buy one, however, you can do so with confidence knowing this unique machine, when properly maintained, is sure to allow for dependable snow travel while getting attention and turning heads all at the same time.