The axle shaft seal in your car is a gasket that keeps fluid from leaking out of the vehicle’s differential. The differential itself is what sends power from the engine of your car to its transmission, and finally to its wheels, allowing them to move. Like all moving parts, the differential has to be lubricated, along with the axle. The seal is mounted either into the differential case or the axle shaft tube, depending on the design of your car. If it becomes damaged, then transmission fluid is going to leak out, causing damage to the transmission, the differential, or both, resulting in costly repairs.
The axle shaft seal is not a moving part, but it is always working. Its job is simply to stay in place and prevent fluid leaks. Barring contamination, it could conceivably last you the life of your vehicle. It requires no maintenance, and only needs to be replaced if it becomes damaged. If it does fail, or begins to fail, you will notice the following:
- Low transmission or differential fluid
- Puddles of fluid near the front wheels
Fluid leaks should never be ignored, because if the axle shaft seal does fail, you could end up with a seized transmission. If you are losing any significant amount of fluid, you should consult a professional mechanic without delay and have the failing part replaced.