In 1951 the Army awarded a contract to the Ford Motor Co. for the design and development of a completely new 1/4 ton vehicle to replace the current M38 and M38A1 Jeep. After extensive testing of prototypes and preproduction models, the M151 went into quantity production in 1960. Later updates resulted in the M151A1 and M151A2, as well as the M718 field ambulance. The vehicle featured unibody construction with front and rear independent suspension. When combined with the vehicle’s high center of gravity, the independent suspension resulted in a high percentage of rollover accidents. A completely redesigned rear suspension on the M151A2 eliminated this problem, but by the late '70s the government had already decided not to make any further surplus sales to the public. Known as the "Mutt," the M151 series was also manufactured by Kaiser Jeep and AM General.