Sarge

My wife's 535xi wagon (automatic) has about 109k miles on it, and I'm in the midst of changing engine, trans, diff and transfer case fluids. Unfortunately I've found I have an apparent leak in the vicinity of where the rear driveshaft connects to the transfer case.

Has anyone else run into this?

I changed the transfer case fluid (PITA dropping the exhaust and removing the brace to get access to the fill plug). I'll have to save real work on the transfer case for later, as I imagine I'm going to have to replace the seal, or worse? Is it a bigger problem than that? Apparently you have to be VERY precise about re-torquing the nut that holds the driveshaft flange in place.

Foreign territory for me on this one, so any expertise would be appreciated. Hopefully I don't have to replace the whole box?

Thanks for any thoughts...

Sarge

After changing the fluid, it wasn't really low, and the in/out ratio was roughly the same, so whatever the leak is must be pretty minimal (judging by the dirty scum on the heat shield, it's not new either). I guess I'll just keep an eye on it at oil changes and see if it deteriorates any further. If anyone else has had issues with this, please post...

padre

You replace output shat seal only. Had similar problem, in my case I could see fluid dripping on the exhaust pipe.

handyben

Hi Sarge, to get access to the transfer case fill plug did you have to drop the exhaust completely or just lower it a bit? I tried doing the oil change last summer on my 2008 535xi, but gave up on the idea when I realized I had to lower the exhaust to remove the fill plug. TIA.

Ben

Sarge

Yes, I read somewhere that it might be possible to use a long arm allen wrench, and I tried that, but ended up dropping the exhaust anyway.

If you do drop the exhaust, I would recommend getting some new exhaust flange gaskets where it connects, as the old ones are not very salvageable.

twh

Need to be very vigilant with leaks in the transfer case. There is only 0.55 quart of fluid in there and that isn't much to leave room for leaks.

Sarge

That's very true. Mine appears to be a minor 'weep' of oil around the seal, so I'll have to replace it at some point soon. I may do it when I do the actuator, I'm just trying to figure out if anyone else has had the actuator gear problem, as a lot of people seem to have seen on other xi/xdrive cars, but I'm still looking for info on the e60 (I've seen the same reports on E83, E53, and E90 cars so far).

Here's an overview of what people have found on the E83 X3

gman6262

This is a response to an old thread, but I ran into the same problem and thought I would share what I found just in case it can help someone else down the line. There are two places where fluid can leak from the output shaft of the transfer case - there is a traditional round lip seal around the circumference of the output flange shaft - which in my case, wasn't leaking but I replaced anyway. There is a second o-ring which seals the shim washer at the back of the splined section on the same output shaft flange where the centering pin for the driveshaft protrudes from the output shaft flange - in my case - it was this o-ring which was flattenned and started to weep oil. I replaced both seals. \


Traditional lip seal for the outside diameter of the output flange.

Output shaft flange - there is an o-ring just visible at the bottom of the splined section in this photo - will weep and leak oil.