For example, when a car makes a sharp right-hand
tum, the left-side wheels, axle shaft, and side gear must
rotate faster than the right-side wheels, axle shaft, and
side gear. The left side of the axle must speed up and the
right side must slow down. This is possible because
the pinions to which the side gears are meshed are free
to rotate on the pinion shaft. The increased speed of the
left-side wheels causes the side gear to rotate faster than
the differential case. This causes the pinions to rotate and
walk around the slowing down side gear. As the pinions
turn to allow the left side gear to increase speed, a reverse
action-known as a reverse walking effect-is produced
on the right-side gear. It slows down an amount that is inversely
proportional to the increase in the left side gear.