The differential is essentially a device used to split the engine torque in two and is found on modern vehicles as well as four-wheel drive vehicles. When the differential is used, it allows the outer drive wheel to rotate faster than the inner drive wheel when turning. An increase in the speed of one wheel is balanced with the decrease of speed from the other wheel.
In most vehicles there is a differential in the front of the vehicle and one in the rear. In a four-wheel drive vehicle, a differential is needed between each set of drive wheels, as well as one in the front and one in the rear. The differential joins the pinion to the prop shaft. The pinion is then connected to the main shaft of the gearbox.
Damage to a differential is rare and there’s not usually any warning signs of a failure before it occurs. However, if you hear a loud clunk when changing from drive to reverse and back, this could signal an imminent failure of the differential. Another symptom of damage is a grinding noise coming from the driveshaft and lack of power.