I set about revitalizing a 1998 Mercedes E430 last summer. One thing I've noted is that it can tend to make a good bit of noise while driving. I would call it a growl. It's coming from the front and varies with speed. My E430 s RWD and not a 4Matic. So it's not a front diff. It's not clunky, so not cv related. It doesn't seem to vary with engine speed, but rather vehicle speed. I have fresh Conti Pro Contacts on it. It's not tire.

Ideas?