Four Wheel Drive Transfer Case Service and Repair (4x4)

A transfer case is a part of a four wheel drive system found in four wheel drive and all wheel drive vehicles. The transfer case is connected to the transmission and also to the front and rear by means of driveshafts. It is also referred to as a "transfer gearcase" "transfer gearbox" or just "transfer box" axles.

The transfer case receives power from the transmission and sends it to both the front and rear axles. This can be done with a set of gears, but the majority of transfer cases manufactured today are chain driven. On some vehicles, such as four wheel drive trucks or vehicles intended for off-road use, this feature is controlled by the driver.

The driver can put the transfer case into either "two wheel drive" or "four wheel drive" mode. This is sometimes accomplished by means of a shifter, similar to that in a manual transmission.