The '84 300D T had a rattle during certain RPMs and it was the bushing. One thing I did before going under the car was to hold the shifter and apply enough pressure (I believe toward the right side) to stop the rattle. Doing this repeatedly made me certain what I would find. Once under the car, a bushing was gone. Not wanting to wait for a new one to arrive, I fabricated one and it is working. I'll be back under replacing the flex discs, support bearing, etc. so that will be my time to put the real bushing in. Keep us posted so we can learn from your experience.
Steve

__________________
Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
English Bulldog (Brier) - My best friend. Passed away 12/02/04 while in my arms.