Six-wheel drive, 6WD, and 6x6 are terms used to describe a drivetrain which allows all six wheels to receive power from the vehicle's engine simultaneously. Unlike four-wheel drive drivetrains, the system is still largely confined to off-road vehicles, particularly heavy-duty ones. Most six-wheel drive vehicles have two wheels at the front and four at the rear and require the driver to manually switch between drive to the four rear wheels for on-road use and all six wheels for off-road use.
