Oil residue on c63 rear diff casing

[BigChap]

Noticed some oil residue on one side of the rear diff casing, it wasn't think and wet but was still pretty fresh. It looked to be completely my from higher the the shaft seals, my mot mate reckoned it could be from a breather higher up on the casing and out of sight. Anyone had this can confirm the breather possibility?

It'll be heading for a service soon so be good to have an answer when they call up and say the diff casing is gone and the bill will be £4K etc! Could be an excuse to get that lsd ordered up!

 

[Felstmiester]

If it's not any of the seals on the shafts your mate could be right. Not over familiar with the c63 diff but I know on the old e39 m5's we used to fit a longer vent pipe higher up because they suffered from kind of over pressurising and venting fluid out the standard breather. Without the mod you was changing the seals regular. Maybe worth looking into.

 

[Lee C63]

Had the same thing happen to me.
Breather can open when oil gets hot and then not re-seal.
It's only a few quid for a new breather, and easy to change. Just pulls off and new one pops straight on