My 99 MCoupe lost/broke a circlip holding the lrear axle into the diff (so the service dept said). It leaked, rather slow drips when hot. The message I got was that a few early production cars had out of spec circlips which failed. They replaced the entire diff. Works fine now. I have a leak from the rear of the car! I think it is oil, it looks like it is coming from the slip diff. has anybody had this or have any ideas what this might be.