I have had this problem with a 190E. It would do it itermittently for a week (sort of a clicking noise from stop until abouy 25mph). I could not duplicate the noise on jacks nor could I find anything wrong with the car. It went away and came back about a year later for a week. It has not return and it has been about a year and a half.
Let us know what you find out, because others have had the exact same problem. Check out prior posts on this subject.

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1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T