What is a Transfer Case?
A transfer case is the component on a four wheel drive or all wheel drive vehicle which transfers the drive from the gearbox to both the front and rear axles via prop shafts. The distribution between front and back can be controlled electronically or manually by the driver. Most transfer cases today run on a chain system rather than gears.
How Transfer Cases Work
Different settings of a typical chain driven 4X4 transfer case;
2WD/2H (high range)- This is usually used for everyday driving where the transfer case will only drive either the front wheels or the back wheels. This is used for high speed driving.
4H (high range) – This is usually used for low speed, dirt road or snow(slippery surface) where the transfer case will drive both front and rear axles at the same speed.
4L (low range) – This is also referred to as the crawler gears. In 4WD low, the ratios will produce a very high torque at a very low speed where the transfer case is driving both front and rear axles.