A transfer case is a component in some four-wheel drive (4WD) and all-wheel drive (AWD) vehicles used to manage the power distribution between front and rear axle(s). The transfer case does this by providing two separate output shafts, each with its own gear ratio, which can be sent at different speeds to the front and rear axles.
The main purpose of a transfer case is to enable drivers in Meridian, MS to select high or low-range gearing. It also enables the driver to engage or disengage 4WD operation. Transfer cases are often part of the center differential unit along with other components, such as propeller shafts, differentials, and drive shafts.
Some light trucks have transfer cases with two modes; 2WD mode for normal driving conditions and 4WD mode for extra traction in slippery conditions, such as snow or mud (or both).
A typical 4x4 vehicle has an open differential on each wheel. This means that if one wheel loses traction, due to dirt, gravel, etc., then all wheels will spin at the same speed until that wheel regains traction.