Yeah, the upper eye of the damper has a rubber insert and they dry out..causing the bond between the rubber bushing and the metal eye to seperate. When this happen, the damper slides from side to side, causing the rattle..the screwdriver test/trick just takes the slop out by jamming it in the space.
If one takes the bolt out and sandwiches an O ring in between the damper eyelet and the frame [ around the bolt] . it stops the side motion and the problem is permanently solved..
The rubber bushing does not wear out, so the damper still works fine, it just floats in the eye ,,so the O ring stops the lateral movement. I have done tons of them and they have never failed again, so it is not a bandaid fix......
I have a DIY article in the archieves on it somewhere ...

EDIT
Found it,,
All M104 engine owners, Please Read