The M6 High Speed Tractor

This tractor was designed as a prime mover for the 4.7-inch (later in the war renamed to 120-mm anti-aircraft gun) anti-aircraft gun, the 8-inch gun, and the 240-mm howitzer. It was of the crawler or track-laying type with tank-type tracks and suspensions, and could be used for either highway or cross-country travel, or where mountains, swamps, sand, or small unbridged trenches would be encountered. The tractor had two forward speed ranges, one reverse speed, and an engine brake gear for descending hills. Because of its low center of gravity, the tractor was capable of climbing slopes which may be as steep as 30 degrees, depending on the kind of footing available and the load being pulled.

4.7-Inch A.A. Gun (120-mm A.A. Gun) on flat rail car during transport.

8-Inch Gun

240-mm Gun

The M6 viewed from all sides

The front of the vehicle and a detailed view of the front left windshield

The driver's position. Steering was accomplished by means of a controlled differential. The action was controlled by means of brakes and handbrake levers.

Suspension and tracks. The tracks were of standard ordnance design, each consisted of 83 blocks connected by connectors and wedge bolts on ends of pins. Track guides were in center of track. Flexing of the track was made possible by rubber track pin bushings. Chevron cleats welded to the track blocks provided traction.

The Seating Arrangement. The cab was divided into two compartments. The front compartment seats the driver and four other men, while the rear compartment accommodated five more men. The seat cushions were padded canvas zipper bags; the back cushions were leather-covered.

Power was supplied by two Waukesha 6-cylinder, water-cooled, 4-cycle, valve-in-head gasoline engines, each with a minimum rated horsepower of 210 at 2,100 revolutions per minute.

Tools and equipment on the tractor included a cranking motor, fire extinguishers, electric and air trailer brake controls, and winch. A gun ring in top of cab provides for mounting of a caliber .30 or caliber .50 machine gun. A combination ammunition and cargo box at the rear of the tractor provides for carrying of dunnage, water, oil, and ammunition. Vehicle and gun tools are carried in a box in rear seat compartment. Pioneer tools and spare track blocks are carried in brackets on the roof of the cab.


- SNL G-184, The Standard Nomenclature List for Tractor, High Speed, 38-Ton, M6 (Allis-Chalmers), 1 March 1944
- TM 9-788, Tractor, High-Speed, 38-Ton, M6, 25 July 1944
- TM 9-788, 38-Ton High Speed Tractor M6, May 1952

The M6 Lubrication charts

Some pictures of a restored M6