Four wheel drive allows a vehicle to supply power to all four of its wheels. Drivers depend on four wheel drive systems to give them better traction on snow, ice, and off-road terrain. Vehicles with 4WD can be full-time or part-time.
Locking hubs, also known as free wheeling hubs, play an important role in four wheel drive systems. Usually located on the front wheels of part-time 4WD vehicles, locking hubs are used to engage the front wheels and transform them into drive wheels as needed.
Four wheel drive systems operate with the help of a transfer case, a type of gearbox that is usually located behind the transmission. The purpose of the transfer case is to help the vehicle apply the correct amount of torque required by the driver.
A transfer case is one of the serviceable components in a four wheel drive system. Present in both full-time and part-time 4WD vehicles, the transfer case operates with the help of gears and, in many modern cars, a chain.