An axle seal is the part of the vehicle that connects the axle to the rear differential, or the transmission. The purpose of the axle seal is to keep transmission fluid from leaking. Depending on the size of the leak, it may be okay to drive with a leaking axle seal, but not for very long.
If you are concerned about a leaking axle seal, here are 2 things to look out for:
Oil puddle under car. One of the more common signs the axle seal is leaking is oil below your vehicle after it has been parked. Your driveway is one of the spaces you will notice the oil leak. If you start to notice oil drops on your driveway, it could be a sign of a leaking axle seal.
Transmission slipping at highway speeds. While an oil spot on the driveway is a common sign, it does not always happen because the axle seal leaks more during highway driving. Instead, you may notice your transmission slipping at highway speeds. Since the transmission fluid drops, there is not enough fluid for brake band friction, valve operation, gear lubrication, and the torque converter. If the leaking axle seal does not get fixed soon and the transmission is slipping, you could cause permanent damage to the transmission.
The severity of the leak affects how safe it is to drive with a leaking axle seal. If there is significant fluid loss, so much that it affects the transmission, the vehicle should not be driven. If the leak is small and you can’t make it to an appointment for a few days, it is okay to drive your vehicle as long as you keep the transmission fluid full. Do not push it too far though, as ruining your transmission is an expensive repair.
The most common cause of a leaking axle seal is it improper axle installation or removal. In addition, the axle seal can wear out over time, which can cause it to leak. A leaking axle seal may be covered by your vehicle’s Powertrain Warranty, so check your car’s brochure to see if this is the case.
If your vehicle has a small axle seal leak, it may be okay to continue driving for now, but you should look to have your car's axle shaft inspected and potentially replaced immediately. Make sure to keep your transmission fluid full so your transmission keeps running smoothly. If you have a large leak and your transmission is slipping, it is not a good idea to drive with a leaking axle seal.