The M246 Truck, Tractor, 5 ton, 6x6, Wrecker is part of the G-744 (or M-39) series of 5 ton 6x6 trucks. Details of the history, model numbers, and configurations of the M39-series of trucks are on the linked page.
The M-246 is a medium capacity truck-tractor wrecker intended for general utility in reclamation, maintenance, and supply activities. It consists of an Austin Western hydraulically-operated crane unit mounted on a standard M-39 series five-ton, 6x6 truck chassis. The M246 tractor-wrecker truck has a 215-inch Long wheelbase, 12:00x20 tires, and dual rear wheels.
The vehicle is provided with a fifth-wheel plate attached to the truck frame behind the crane assembly for the purpose of towing a military semitrailer. The normal rotation of the crane is restricted to 270 degrees; however, 360 degree travel is possible by removal of stops. The boom can be raised from the horizontal position to an angle of approximately 45 degrees. In addition to the vertical movement of the boom, the boom can be extended from 11 1/2 feet to 19 feet hydraulically and from 19 feet to 26 feet manually. The crane is normally rated at a 10,000-pound capacity, but, as a fixed crane, it was designed to have maximum lifting capacity of 20,000 pounds with 15-foot boom extension, jacks positioned, rear outriggers up, and using a three-part line. Power for the crane is supplied by a hydraulic pump driven by a power take off from the truck engine.
The weight of the M246 is 32,000 pounds and it is 29 feet 7 inches long, 8 feet 2 1/2 inches wide, and 11 feet 2 inches high.