Willys was the largest supplier of jeeps to the us army. The nick name jeep actually came from the army reference of these as general purpose or gee pee vehicles, which evolved into jeep. In 1944, Willys-Overland, one of the two main manufacturers of the World War II military Jeep, built the first prototypes for a commercial version – the CJ, short for "civilian Jeep". The Willys-Overland CJ-3A was introduced in 1949, and was in production until 1953, when replaced by the CJ-3B. It was powered by Willys' 60 hp (45 kW; 61 PS) L-134 Go-Devil four-cylinder engine, with a T-90 transmission and Dana 18 transfer case, a Dana 25 front axle and Dana 41 or 44 rear axle. 1951 - 52 is considered to have been the best all around production year.