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How Does a Transfer Case Work?

The transfer case is an integral part of the four wheel drive system of a motor vehicle. Its purpose is to turn the vehicle into an all-wheel drive when necessary by allowing the axles of the front and rear to move together. To do this the transfer case forms a part of the drive shaft. This is the part of the vehicle that transmits power to the drive train. Through the drive shaft the transfer case also connects to the transmission (part which sends signal to change to four wheel drive) and the front and rear axles (points where signal for four wheel drive manifest).



Mechanism of Action of the Transfer Case



Bear in mind that the purpose of the transfer case is to achieve four wheel versus two wheel drive. When it receives the signal via the transmission, certain conformational changes take place to ensure that happens. Below is a step by step process of just how the transfer case works to provide four wheel drive.



  1. The transfer case located on the drive shaft receives a signal via the transmission. The signal from the transmission generates from a change in the gear by the driver of the vehicle. In this case the driver would switch to the four wheel drive gear/s options in the vehicle.
  2. The transfer case interprets the message and relays it to the axles; both front and rear.
  3. When both axles operate at the same time the vehicle is in four wheel drive and can withstand off-road conditions such as bad weather and rough terrain.


One must also remember that a transfer case can also provide two wheel drive systems. The mechanism of action is the same as with four wheel drive except only one set of axles receives signals from the transfer case. If the rear axle receives the signal then the vehicle is in rear wheel drive and if the front axle receives the signal, the vehicle is in front wheel drive.

The transfer case allows some vehicles to have dual purposes and allows them to cross through otherwise forbidden terrain. In its most popular function, the transfer case facilitates two wheel drive systems. However, in a more exciting function it facilitates the four wheel drive system. This devices facilitates all-wheel drive by collaborating with the gears, transmissions and the axles of the motor vehicle to produce a vehicle that can go from on-road to off-road conditions with ease.