Permanent Four-Wheel drive
As the name suggests, permanent Four-Wheel drive sends torque to all four wheels "permanently" (continuously), on or off pavement. There is no two-wheel drive mode, and the driver doe not need to determine when to engage Four-Wheel drive mode. Drive selections typically include Four-Wheel drive High and Four-Wheel drive Low. Most permanent four-wheel drive systems also have a slip-limiting device plus a two-speed transfer case. Land Rover Discovery Series II and Range Rover use permanent Four-Wheel drive.