It could be any number of things. If you aren't mechanically inclined, bring it to an independent, unless you have bags of money. If you have bags of money, then a stealership will do.

If the indy is not MB savvy, have him take a good look at the set-up. I am sure he'll agree he can tackle the job. Parts can be bought here or any number of on-line parts places. No need to enrich your local stealership.

__________________
Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport