The 4x4 transfer gearbox is the unit in the vehicle attached to the output of the gearbox. Its function is to direct power to both front and rear axels, in varying ratios depending on the manufacturer. Many of these units also allow a lower range to be selected, more power for more rigorous off road conditions. They can be manually operated on earlier models, such as Land Rovers, Cherokee Jeeps, Mercedes G Class etc, or electrically on most modern vehicles. Some are now automatically operated by the vehicle as it determines the conditions of the terrain and the vehicles handling. 

Due to the fact that all the drive is transmitted through the transfer box, and the nature of the vehicles and there use, (heavy 4 x 4s and off road driving), the 4x4 transfer gearbox is under a huge amount of strain. This can often lead to premature wear and failure. 

Like other mechanical parts on the vehicle, such as the engine, brakes and automatic gearbox, the transfer box should be maintained to limit possible problems. A simple oil change and replacement of leaking seals could save costly repairs. We recommend this service is done every 40,000km along with the automatic gearbox..