The M-936 Truck, Medium Wrecker: 5-ton, 6x6 w/winch is part of the M-939 Series of 5 ton 6x6 trucks. Details of the history, model numbers, and configurations of the M939-series of trucks are on the linked page.
The M936/A1/A2 series wreckers are designed for recovery of disabled or mired vehicles, and perform crane operations. The crane extends a maximum 18 feet (5 meters), elevates 45 degrees, and swings 360 degrees. It is capable of lifting loads up to 20,000 lbs. (9,090 kg). A second hydraulic winch is installed at the rear of the vehicle.
The dimensions of the M-936 Truck, Medium Wrecker: 5-ton, 6x6 w/winch are: