Axle Shaft Seal
A seal at the ends of the axle housing or transmission case that prevents fluid from leaking around the axle shafts.
An axle shaft seal is a round rubber and metal gasket designed to prevent gear oil or transmission fluid from leaking out of the axle housing or transmission casing where the axle shafts exit. On front-wheel-drive vehicles, these seals are located in the transmission case around the inner CV joints. On rear-wheel-drive vehicles with a solid axle, they are located at the outer ends of the axle housing, near the wheel bearings.
The seal must seal against the spinning surface of the axle shaft. If an axle seal fails, fluid will begin to leak. On front-wheel-drive cars, this can lead to low transmission fluid levels and transmission damage.
On rear-wheel-drive trucks, a leaking outer axle seal will coat the brake shoes or pads with gear oil, severely reducing braking efficiency and causing smoke or a burning odor. Replacing the seal requires removing the axle shaft and pressing the new seal into the housing.