Edward's Transmissions+ Auto Systems Expert - Castleton

Tech Tip Tuesday: The Differential

The differential is the component that lets the two wheels on a driven axle rotate at different speeds. That matters because every time a vehicle turns, the outside wheel travels a longer path than the inside wheel.

Without a differential, one wheel would have to drag or skip through every turn. With one, both wheels maintain traction while still delivering power through the drivetrain.

Differential problems produce specific symptoms. A whine that changes with vehicle speed. A clunk or grinding during turns. A howl that gets louder under acceleration and quieter off-throttle. Gear oil leaking from the rear of the axle housing.

Most differentials call for a gear oil change every 30,000 to 60,000 miles, more frequently for vehicles that tow. Neglecting that service is one of the most common contributors to differential wear and eventual rebuild.