Allis-Chalmers M7: The Abominable Snow Tractor

Vintage vehicle still a hard-working winter warrior


| February 2010



Sons Curtis and Forrest with their dad (Clell Ballard) on an outing in M7 no. 177

Sons Curtis and Forrest with their dad (Clell Ballard) on an outing in M7 no. 177. Skis and a toboggan are included for recreation, but also as back-up transportation in case of a major mechanical breakdown.

courtesy Clell Ballard

Farm Collector recently ran an article about an impressive restoartion of a rare 1944 Allis-Chalmers M7 military snow tractor.

(Read “ Allis-Chalmers M7 Restoration ,” by Bill Vossler, November 2009.)

With a production run of just 291 (all in 1944), very few M7s are still in existence. Even dedicated collectors who would like to have one of every tractor AC produced have found that obtaining an M7 is next to impossible.

Search for a snow tractor

As strange as it may seem, at least a couple of those elusive tractors are still doing what they were designed to do more than 65 years after they were built: provide transportation in deep snow where other vehicles never go.

My brother, Claude, and I both own M7s and use them in the high mountains near the totally unsettled area of central Idaho. Claude’s first exposure to the snow tractor was in the early 1950s when, as a Boy Scout, he and his fellow Scouts were transported into the rugged Sawtooth Mountains by Idaho Fish & Game Department officers. The wintertime exercise trained the Scouts in survival skills in primitive conditions. At that time the vehicles (which had been obtained from U.S. Army surplus) were fairly new and had proven themselves with the department for use on extended trips far from civilization. In deep snow (depths of 10 feet were not uncommon) and extreme temperatures (dipping to 25 below zero), the M7s were depended on without reservation.

In 1978, after the Fish & Game Department retired the vehicles, Claude traveled almost 1,000 miles round-trip to buy his M7 (no. 255). He also got a large number of spare parts, including two extra tracks – a real plus, as there is no known source for parts. Since so few machines were built, the military purchased only the minimum number of parts needed.

I stumbled on to an M7 (another ex-Fish & Game vehicle) at a bankruptcy auction a few years later in an area where it rarely snows. Although my financial resources were very limited, I managed to buy the M7 (no. 177) because the auction was held on an August afternoon when the temperature was near 90 degrees. Since they didn’t live in snow country like I did, the other bidders weren’t very motivated. Later in the auction another M7 (no. 195) was auctioned off. Its condition could only be described as “a hulk.” I bought it, too, for the princely sum of $40.

Winter warrior

We live in an isolated mountain valley at 5,000 feet elevation with low mountains on the south and peaks reaching over 10,000 feet on the north.

Because of extremely harsh weather conditions, fewer than 1,000 people live in a county about the size of Rhode Island. Snow is on the ground most of four months at a depth of about 3 feet on the flat and much deeper in the mountains – the ideal location for someone with an Allis-Chalmers M7 snow tractor. Although our homes are in a small village, my brother and I can go out to garages where our snow tractors are stored, fire them up and strike out across a totally white world with nothing to impede our progress.

Claude has a log cabin built on an old mining claim far up in the mountains. The only way to reach it in the winter, with supplies necessary for an extended stay, is with the M7s. My sons and I once spent a week there during a “spring break” in late March. At lower elevations, it would have been spring. At high altitudes, though, winter remains in full swing in late March.

Military M7s had a canvas cab that covered two passengers (one seated behind the other). Idaho Fish & Game modified its M7s by creating larger, all-weather cabs. Several designs were created; all were wood-frame with a solid roof and doors that could be closed. No. 177 could transport five people with the driver in front and the other four sitting facing each other along the sides in the rear. A roof rack held the supplies we’d need for a week in the wilderness.