Transmission leaks are normally found around the pan gasket, but they can also be located in other places. If you’re noticing transmission fluid leaking at the axle, you’ll need to figure out what’s going on in order to save the transmission before something bad happens. Even a small leak can translate to serious damage over time, common among used transmissions for sale. Here are some steps to take if you notice transmission fluid leaking at the axle.
Check the Transmission Fluid Level
Before you do anything else, check the transmission fluid level. Just because there’s visible transmission fluid where the axle enters the transmission, it doesn’t necessarily mean there’s actually a leak there. Checking the fluid level first can help ensure you’re troubleshooting an actual problem and not someone’s mess that didn’t get cleaned up.
Has the vehicle in question had an axle replacement in the recent past? If that’s the case, it might not be a leak so much as its fluid left over from the replacement that didn’t get cleaned up. How fresh is the fluid? Is there any dirt and debris from the road in it? Is it “gummy” and old or is it fresh and relatively clean? If it’s clean and the axle replacement was some time ago, you should suspect a leaking axle seal.
Check Higher Up
While you’re under the car looking at the axle, you should double check to make sure that the fluid isn’t coming from higher up and just running down on the axle. You’ll need a good light to do this. If you notice transmission fluid anywhere else, the best course of action is to clean it all off, drive it and then recheck. This should give you the best idea of where the fluid is leaking from.
If It Is the Axle
Axle seals usually aren’t too much trouble to replace, but that depends greatly on the make and model, as well as whether it’s the driver or passenger side axle seal that’s leaking. At the very least, you’ll need a replacement seal, a circular clip puller (double-hooked pliers, basically) for the clip, and possibly a press if it’s the driver side seal on certain models.
Don’t Forget to Top Off the Transmission Fluid
When you pull the axle to replace the seal (and the seal after that), you’re going to lose transmission fluid. Make sure you remember to top it back off when you’re done (you should just need to fill up the transmission until you can touch the fluid with your finger through the fill hole).