Ford Explorer Rear Axle Seal Question

2010 Ford Explorer 4x4, XLT, 4.0L, 55K miles. This is my wife’s vehicle and I noticed about a month ago that it was leaking gear oil (underneath the rear differential). The amount it’s leaking is very small. I changed the rear differential fluid (thinking it was going to be the differential case) but while I was underneath, it looked like the seal around the axle on the right side was leaking slightly and then dripping down to the differential’s lowest point. We’re going on vacation next week a couple hours away and I have a mechanic nearby to where we’re going to. I made an appointment to have him repair it next Monday. My question: Is the fluid that is leaking from (what I think is) the axle seal the gear oil from the rear differential ? I know it only holds 3.5 pints of 75Wx140 synthetic gear oil since I just replaced it. If it’s the same, would it probably be OK to possibly top it off (that is if it even needs fluid) and then drive ~2.5 hours ? As an FYI, when I did change the differential fluid, it didn’t seem low and the rear end isn’t making any whining noise or driving any different.


The fluid leaking at the axle seal is differential fluid.

The diff fluid flows down the axle tubes on the diff to lubricate the outer axle bearings.

It depends on the rate that the fluid leaks out on how far/long the vehicle can be driven.


Thanks very much Tester. I’m been keeping a careful eye on this and it was barely noticeable when I changed the fluid. I’ll check/top off if needed and then give it a shot on driving it to the mechanic. Thanks again.

If your rear axel is configured like my Ford 4x4 truck, it isn’t a huge job for a mechanic to pull the axel and replace the seal. Well, pulling the axel isn’t a huge job. I’ve never replaced that seal before. But it doesn’t look that difficult or time consuming. When I’ve had rear axel leaks, it has always been from the differential, for me the seal fails where the third member connects to the diff case. That one is a little more difficult to replace, but still isn’t that big of a job.

Some add’l advice, be sure to ask your mechanic to check that the vent is still open. If not the heat generated from driving can sometimes pop the axel seals.

What is an axel ?

The earth rotates on its axel, right? … lol . .

What is an axel ?

This is one of those things that can get expensive VERY fast. A seemingly little leak can get ugly faster than you think. As it leaks out things that should get lube won’t and it won’t take long before the bearings fail leaving you with a very expensive rebuild. The leak can ruin the brake pads or shoes on that wheel as well.

That axle seal is very cheap, $5 each and the labor to get to one is pretty close to the same as 2 so replace them both. It is an easy job but you need to drain and re-seal the cover and refill once new seals are installed.

Once the axle C clip is out it takes seconds to release the second one. Both axles comes out easily and the seal pops out with a puller and the new one goes in. Quick and easy. If one is leaking the second can’t be far behind. Don’t risk a $1500 axle rebuild on a $150-$200 seal replacement.

IF…you leak out enough fluid…
AND… you have a posi-trac, locking diff…
AND all you do is keep topping it off with 75w140 ?
You create a dilution factor , for lack of proper friction modifier, that will eat up you clutches .

fix the leak.

( then go skating and do a double axel. )

This has independent rear suspension, right?

Independent rear suspension since the 2003 redesign, the leak is about 3 feet away from the brake shoes. 1.3 hours to remove and reinstall each half shaft (no C clips).

I’m having a hard time visualizing how the rear drive unit of the vehicle is configured. It’s not a solid rear axle then?

Right, looks like this:

Oohh IRS, not solid axle. I forgot Ford changed them over. Even more important to change the seal, less fluid. I thought that 3.5 PINTS was a mist-type for QUARTS. Bite that bullet and get it fixed.

Thanks for the photo post. Are those rear half-axles equipped with CV joints then? Sort of like front half-axles on a FWD car, only on the rear? CV’s configured as tri-pods on the inner, cages on the outer? U-joints?