Lesson 2/Learning Event 2
When the vehicle is moving straight ahead on a smooth surface, the differential pinion
gears do not rotate on the spider or cross-shaft. As the pinions are carried along with the
differential case, they drive the two side gears at the same speed as the case. Each side
gear receives the same torque.
The right and left axles are splined to the differential side gears and are driven at the
same speed as the turning differential assembly. The outer ends of the two axles drive
the wheels at the same speed.
Let's say that a vehicle goes around a short right turn. Notice that when the center of the
rear axle has traveled a given distance in the turn, the two wheels have traveled two
different distances. The outer wheel had to travel almost 4 extra feet to keep up with the
inner wheel. This means the outer wheel had to travel faster than the inner wheel to
travel the greater distance. This also means the differential side gears travel at two
FIGURE 20. TURNING ACTION.