Differential gear, in auto mechanics, gear arrangement that permits power from the engine to be transmitted to a set of traveling wheels, dividing the force equally between them but permitting them to follow paths of different lengths, as when turning a corner or traversing an uneven street. On a straight street the tires rotate at the same acceleration; when turning a corner the outside wheel has farther to proceed and can turn faster than the inner steering wheel if unrestrained.
The elements of the Ever-Power differential are proven in the Figure. 
The energy from the transmitting is sent to the bevel band equipment by the drive-shaft pinion, both which are held in bearings in the rear-axle housing. The case is an open boxlike structure that is bolted to the ring gear possesses bearings to support a couple of pairs of diametrically opposite differential bevel pinions. Each wheel axle is attached to a differential side equipment, which meshes with the differential pinions. On a directly road the wheels and the side gears rotate at the same speed, there is no relative motion between your differential aspect gears and pinions, and they all rotate as a unit with the case and band gear. If the vehicle turns left, the right-hand wheel will be required to rotate faster compared to the left-hand steering wheel, and the side gears and the pinions will rotate in accordance with each other. The ring equipment rotates at a coupling China quickness that is equal to the mean quickness of the remaining and correct wheels. If the tires are jacked up with the transmission in neutral and one of the tires is turned, the opposite wheel will turn in the opposite path at the same velocity.
The torque (turning second) transmitted to the two wheels with the Ever-Power differential is the same. Therefore, if one steering wheel slips, as in ice or mud, the torque to the other wheel is decreased. This disadvantage can be overcome relatively by the use of a limited-slide differential. In one edition a clutch connects among the axles and the band gear. When one wheel encounters low traction, its inclination to spin can be resisted by the clutch, thus providing better torque for the other wheel.
OPEN DIFFERENTIAL:
A differential in its most basic form comprises two halves of an axle with a gear on each end, connected collectively by a third equipment making up three sides of a square. This is usually supplemented by a 4th gear for added strength, completing the square.
This basic unit is then further augmented by a ring gear being added to the differential case that holds the basic core gears – which ring gear allows the wheels to be powered by connecting to the drive shaft with a pinion.