A driven axle is a mechanism that connects two wheels while transferring drive to them from the chassis. The power is usually received from a driveshaft that is longitudinal to the chassis and perpendicular to the axle. Connecting these two elements is neccessary, and a pair of bevel gears is the simplest solution. But in practice, bevel gears are prone to skipping under high torque, and driven axle is where we can expect high torque This Leaves us with two other potions: a differential or a pair of knobs. A differential is less likely to skip, especially if braced inside a proper structure