Differentials and main gears constitute the final drive system, transferring engine power to the wheels while allowing for varied wheel speeds during cornering. Located within the axle housing, these components utilize a set of gears – including pinion, ring, and spider gears – to split torque and adjust output speed. Ratios are specified by numerical value, indicating the gear reduction between the pinion and ring gear. Limited-slip and locking differentials employ clutches or mechanisms to transfer increased torque to the wheel with greater traction. Component metallurgy and heat treatment are critical for durability under high loads and stress.