【正文】 the loss of driving force that occurs when one wheel begins to slip, special differentials are designed to automatically transfer the torque to the wheel that is not slipping. This enables the car to continue its forward motion. Although there are several variations, all employ the principle of a friction device (clutch plates or a cone clutch) to provide some resistance to normal differential action. CHRYSLER SUREGRIP The Chrysler SureGrip differential is basically a standard model, but with several important additions. The axle side gears are driven not by two differential pinions but by four. This requires two separate pinion shafts. The two shafts cross, but are free to move independently of each other, The shaft outer 8 ends are not round, but have two flat surfaces that form a shallow V. These ramplike surfaces engage similar ramps cut in the differential case. A series of four clutch discs are used in back of each axle side gear thrust member. Two of these discs are splined to the differential case, and two are splined to the thrust member. The thrust member is splined to the axle. When the thrust members push outward, the clutch discs are forced together, locking the axle to the case. SUREGRIP DIFFERENTIAL OPERATIONBOTH AXLES TURNING AT THE SAME SPEED When the propeller shaft drives the pinion gear, the torque thrust is transmitted to the ring gear. As the ring gear drives the differential case, the pinion shafts are forced to rotate with the case. The differential pinions encounter resistance when they attempt to turn the axle side gears. This resistance is transferred to the pinion shafts that aredriving the pinions. As both ends of each pinion shaft are seated in tapered ramps, and since they have some play at this point, this forces the shafts to slide up the ramp surfaces. This sliding movement moves bothshafts n an outward direction. As each shaft moves outward, it moves its pinions in the same direction. The pinions press against the pinion thrust members, forcing them to lock up the clutches. This is the action when the car is traveling in a straight line. AXLES TURNING AT DIFFERENT SPEEDS When the car turns a corner, the inner shaft slows down. When this happens, the pinion gears will start turning on their shafts. They will walk around the slower shaft and speed up the other shaft. This walking causes the outer shaft to rotate faster than the differenfial case, allowing the pinion shaft on the outerside to slide down its ramp. This releases the pressure on the outer clutches and lets the differential unit operate much like the standard model. It shows differential action when one axle is moving faster than the other. Note that the slower moving axle is receiving most of the torque since it remains clutched to the case. This type of differential will provide better traction than the standard differential. It is particularly useful when roads are slippery and is also valuable in producing fast acceleration. A highpowered engine will often cause one wheel to spin during acceleration when using a standard differential. A somewhat different traction differ