Four Wheel Drives

M561 Truck - Gamma Goat.

Gama Goat all tricked up for European Truck trials and showing the degrees of freedom of its unique design.

Mark Limbert writes:

The M561 1.25 ton High Mobility Cargo Truck was built during the late 1960's and into the 1970's by the Consolidated Diesel Electric Company otherwise known as CONDEC. It was nicknamed the Gama Goat, "gama" from the name of the inventor of its powered articulated joint Roger Gamaunt and "goat" from its mountain goat-like offroad abilites.

The M561 was a 6x6 having a tractor unit and a trailer unit. The tractor sat two, a driver and a passenger, above the front axle and behind them was the Detroit Diesel 3-53 diesel engine. Attached to the tractor by an articulated joint was the trailer unit which was of standard military arrangment much like a pickup type bed with the addition of folding troopseats along each side. The tractor and trailer were permanently joined. The tractor had a front axle and a rear axle while the trailer had a mid mounted axle. All axles were powered. The M561 was also four wheel steer, the front steered in normal fashion and the rear most axle was mechanically steered in the opposite direction at 50 percent of the front axles movement. The steering was not self centering.

The M561 body was made of aluminum and the vehicle was swimable on inland waters. This vehicle was capable of higher mobility than the average pickup style truck or 1/4ton jeep due to its ability to flex in the middle and the forward position of the front wheels.

The Gama Goat was a successful offroad vehicle but due to a plague of mechanical problems, its loud engine noise, and special driver training because of its four wheel steering habits it was not pursued in future contracts and was eventually replaced in function by the M998 series HMMWV (High Mobility Multipurpose Wheeled Vehicle).

Go to the M561 or Military Vehicles pages