Thanks for the input guys.
As you might imagine, the first place I looked (after checking the trunk) was the rear suspension. Everything seems to be intact and securely fastened. And too, what part of the suspension could "slide" from one side of the car to the other?
Leathermang - In response to your G-force question, my wife and I are in our seventies and I assure you neither of us tries to hot-rod it......especially in a 24 year old 240D.
Mike - Yeah, I realized when the gauge ceased to work that I was going to have to go into that sending unit eventually. I just don't look forward to it and tend to procrastinate on jobs like that. May have avoided this noise problem if I had gone ahead and done it. We'll see.
Appreciate all of your responses.