Leaking Rear Differential


While bleeding my brakes today I noticed that my rear differential appeared to be leaking. No drips on the floor, but the bottom of the differential was wet where I touched my finger to it. I’m trying to figure out how to post a picture.

Question is, is this amount of oil on the outside of the differential normal? Is it indicative of anything other than I need to change the gasket?

'95 Mercury Couger V8, 167,000 miles.


Hopefully I just attached 2 pictures.


The car has independent rear suspension and the leakage appears to be coming from the axle shaft seals.

This is normal with time/mileage and will hurt nothing if the fluid is not allowed to get too low. It usually looks worse than it actually is.

Either keep an eye on the fluid level or change the seals if they are a concern.
Generally speaking, if the fluid starts to get low enough to be a concern the differential will start to whine.
It’s best to keep an eye on the fluid level and avoid the whine altogether.

Hope that helps.


Don’t wait for the gear whine. This means the gears are getting damaged. Check the fluid level. A very little bit of gear lube can make a scary mess, so chances are you’re not losing much. But, keep an eye on it. Usually, these seals will get worse and leak more gear lube, but it may be a long time, like years, to get to a point where you’ll need to change out the seals. I’ll usually wait until I see drops forming under the car when parked.


Thanks to both OK and Busted Knuckles for the advice. I’ll check the level tomorrow, and probably about everytime I change engine oil for a while.