MIL-T-740G, MILITARY SPECIFICATION: TRUCKS; 5 TON, 6X6, MILITARY DESIGN, M39, M39A1, M39A2 AND M809 SERIES (27 MAY 1983)., This specification covers general and special purpose 5 ton, gasoline, multi-fuel, and diesel engine powered, six-wheel, six-wheel drive, military design truck chassis, trucks, and truck tractors having single front and dual rear wheels.