Ford Escape: Automatic Transmission - Automatic Transmission – HF45 / Description and Operation - Differential

The differential allows the halfshafts and wheels to rotate at different speeds during cornering. The differential assembly consists of the following components:

• Differential carrier
• Two pinion gears
• Two side gears

When driving in a straight line, both front wheels rotate at relatively the same speed. This means both side gears are rotating at the same speed as well, while both pinion gears revolve (but do not spin) with the side gears in the differential carrier. During cornering, the wheel on the outside of the turn is forced to rotate faster than the wheel on the inside of the turn. Since the side gears must now rotate at different speeds, the pinion gears rotate on the pinion shaft allowing the drive axles to rotate at different speeds while still transferring output torque.