A couple of weeks ago during some very very very cold weather, I noticed some fresh spots of oil under the rear of the vehicle. Today I finally investigated and here's what I saw.

First, a photo of the diff taken directly from the rear. Notice the oil at the leftmost bottom of the diff.:


Second, a photo taken from the driver's side rear, as far as I could reach the camera under the vehicle:


As far as I can tell, the CV axle seal on the diff is leaking. Any other opinions? Our bumper to bumper warranty is still in effect, so I am assuming this will be covered under warranty, correct?

Thanks

 

you need a rear differential output shaft seal. $5 from Rockauto.

I did this last christmas time.

• Remove the wheel
• Remove rear speed sensor and then remove the rear hub
• Remove the CV shaft and inspect the surface that the seal rides on. Mine was worn, but not excessively. Our thoughts were, if we change the seal and it still leaks, no we know and the seal wasn't that expensive.
• I measured the depth that the old seal was installed compared to the outside of the housing.
• Very carefully remove the seal. Bure sure not to damage the differential housing mating surface.
• I measured the differences between the old seal and new seal. I also performed some measurements so that I could fit the new seal in a slightly different location to provide a better seal.
• Put some gear oil on the new seal to lubricate it some and get it started in the housing
• If available, use a large socket or something of similar diameter to push the seal into position. **There is no lip on the diff housing to prevent the seal from being pushed all the way in...be careful! Also, the seal must be as close to perfectly installed the same depth all the way around. It will not seal correctly if it is ****-eyed.
• Slap everything back together.

 

I assume that the cost of replacing the seal is going to be completely covered by the bumper-to-bumper warranty, but after our warranty runs out I'll definitely do the job myself, so many thanks for your precedure.

If it is indeed covered by warranty, because the other side's seal is probably on the verge of starting to leak, I'm going to propose to the stealer that they do the other side proactively on the same "visit", but I think that is probably a bridge too far.

Is there any danger that the rear diff fluid level could ever get too low with this kind of leak? The upper level of fluid seems to me to be below the centerline of the output shaft, but, still, the thing is actually leaking so there must be fluid in that area. The gears inside must somehow transport or splash the oil into that area. How low could it go is the question.

 

your leak looks a bit more than mine, but mine had been leaking for about 3-4 months. when I put the new seal in, I checked the fluid level and it was fine.

 

I would think it would still be covered. Oddly enough, mine leaked on the driver's side too.

 

I sent the above two photos to the closest Mit dealer and got a phone call soon after from the service manager. In short, the seal will be replaced under warranty.

After receiving the call, I took the opportunity to write back and ask what they thought about replacing the one on the other side proactively. I received by email what I thought was a very interesting reply:

"Unfortunately we can only replace the parts that have a defect, and the definition of warrantable is leak such as yours. Mitsubishi Canada does not consider “sweating” as leaking."

I found the word "sweating" rather curious because I had not said anything about any leak of any size on the passenger side. So I looked at the first photo again, and now I understand why he said what he said. My attention was so concentrated on what was going on on the driver's side, I failed to notice what I now believe (and apparently he must have also believed) is a layer of, for lack of a better expression, "grime" on the passenger side that is amazingly similar in color and "texture" to grime on the driver's side, albeit the areas that are not dripping with oil. Take another look at that first photo and see if you agree.

If in fact the passenger side is "sweating" (which I've never seen in any properly-functioning similar-design seal before) I believe that it won't be long before it's leaking as fast as the driver's side and I'll be in there again to get that one replaced. (Being a cynical person when it comes to stealerships, I had to wonder if the dealer makes more money doing two separate jobs rather than two seals on one job.)

Our 1992 Accord had two of these seals on its CV axles and they never leaked, "sweated", or anything else. The area underneath them was perfectly dry. The same was true of the crank seal.

The manager also volunteered that in the case of oil leaking from those seals, "9 out of 10 times" it was the seal only that had to be replaced, but there was a remote chance that the axle itself had damaged the seal and in that case the axle would have to be replaced, too. I don't remember exactly how he said that the axle could do that, but at least I now know that that is possible. The significance in that case would be that although they have the seal in stock, they don't have an axle in stock, so the axle would have to be ordered, requiring me to make another trip to the dealer. I was hoping to get this all done on one visit.

At least the repair is not going to cost anything other than hassle, and in this "artic vortex" weather, I'll gladly accept the hassle.

 

glad to hear they are taking care of it under warranty. I can see the axle being questioned as the shaft that inserts into the diff did have some wear on it. However, once the new seal was installed, it was tight enough I don't think it'll be an issue. When you take it in, ask them to wipe off the passenger side so you can monitor for new leaking. Might help to hint that you'd be back if/when it happens.

 

Today the seal was replaced at no charge. Good. Unfotunately there was a fairly big scratch on the door of the vehicle that was not there when I brought it in. Oh, stealerships! Don't you just love them?

 

That would **** me right off....