Shifter buzzing/rattling 1700 to 2000 rpm

[EDBSO]

That pretty much summarizes it. 1999 E300. I have a loud very distracting buzzing/rattling coming from my shifter in the 1700 to 2000 range.

I can remove the shift knob and the surrounding wood trim and can feel the buzzing rattling with my fingers while I drive.

It is as though there is something loose in there moving rattling/buzzing around.

Fresh Lemfoerder motor mounts and transmission mount and the engine is smooth. There is just this one resonate frequency between 1700 and 2000 rpm that makes the noise.

It is not obvious how to get into the shifter mechanism. I believe that it is a fairly expensive part and I don't want to screw it up BUT it is driving me to distraction. I do tend to be sensitive to unusual noises etc. The diesel is otherwise music to my ears.

Any photos or exploded views of the inside of this mystery shifter box and directions on how to get in there and silence it.

Anyone else experiencing a similar noise? I have been tempted to spray foam it but that would likely cause other problems.