The Gama Goat was a six-wheel drive semi-amphibious off-road vehicle originally developed for use by the US military in the Vietnam War. The Goat uses an articulated chassis, so that from distance it appears to be a four-wheel drive vehicle pulling a two-wheel trailer, but it is a single six-wheel vehicle with a four-wheel steering arrangement with the front and rear wheels turning in opposite directions. It was famous for its ability to travel over exceptionally rough and muddy terrain.
Gama Goat
Gama Goat ride at the Muckleburgh Collection 2005
Six-wheel drive is an all-wheel drive drivetrain configuration of three axles with at least two wheels on each axle capable of being driven simultaneously by the vehicle's engine. Unlike four-wheel drive drivetrains, the configuration is largely confined to heavy-duty off-road and military vehicles, such as all-terrain vehicles, armored vehicles, and prime movers.
A United States Navy Oshkosh MTVR, a six-wheel drive military truck with full-time all-wheel drive and super-single tires on all axles
6-wheel British-manufactured military Alvis Stalwart 6×6 with three evenly spaced axles and full-time 6x6 H-drive
Mercedes-Benz G63 AMG 6x6 with twin rear axles
6x6 Tatra 93 (1938)