The Gama Goat was a six-wheel-drive semi-amphibious off-road vehicle originally developed for use by the US Military for the War in Vietnam. It was famous for an articulated body, which allowed it to travel over exceptionally rough terrain and for a unique four-wheel steering arrangement with the front and rear wheels turning in opposite directions.
The vehicle's nickname came from two sources; "Gama" from the name of the inventor of its powered articulated joint, Roger Gamount, and "Goat" for its mountain goat-like off-road ability. Its military designation was M561, 6x6 tactical 1-1/4-ton truck. There was also an ambulance version known as the M792 that could carry four litters.
The concept for the vehicle came when the French Army reported that the US Army trucks provided to them were woefully inadequate for the terrain in Vietnam. In 1959, ARPA (now known as DARPA) funded a research project called Project Agile to develop a new tactical truck for the Southeast Asia theatre, as well as other projects of interest to the then-looming Vietnam War.
Several companies bid for the contract, including Clark, General Motors and LeTourneau, but the contract was awarded to Ling-Temco-Vought (LTV) aerospace, best known for their A-7 Corsair II aircraft. Final construction of the vehicles was conducted by Consolidated Diesel Electric Company (CONDEC) at their factory in Charlotte, North Carolina. CONDEC also had factories in Schnectedy, New York, where the Gama Goat was originally manufactured, and in Greenwich, Connecticut, where the parts for the Gama Goat were produced. In the early 1960s, the company moved to Waterbury, Connecticut for a few years, then closed their plants in New York and Connecticut to move to Charlotte, North Carolina for cheaper labor and facilities.
The air-cooled engine used in the original prototypes overheated and was replaced in the production vehicles with a Detroit 3-53 diesel engine. The high intensity noise from the 2-stroke diesel engine resulted in a warning to all operators that hearing protection was required while driving the vehicle. The double hull construction and complex articulated drive train made maintenance difficult (the lube order alone took around six hours). In service in Vietnam, Gama Goats would often be sent out ahead of other vehicles, in order to arrive at their destination at the same time. Their loud engine noise made them much less than stealthy. The 'Goat is prized among military vehicle collectors because it is so unusual and in short supply. The vehicle was replaced by the CUCV and HMMWV.