After 11k miles with my 2006 MCS and no problems a few days ago a viseral kind of muffeled grinding sound is coming from somewhere after the engine output shaft. It is in sync with the wheel rotation speed. I have a limited slip with no mods. This noise came on right after a stop, no warning but is not so loud that the radio will drown it out. I will be taking it in shortly for it's first service but has any else had this happen? PEZ

 

It turned out to be a bad wheel bearing...failing at 11K. Dealer has to order the part so there keeping my MCS for 5 days...they would not let me take it back saying it was a safety issue. I have seen drastic wheel bearing failures before....not pretty. PEZ