The vibration/noise problem on my 83 240D manual transmission (142K miles) has finally been narrowed down to the transmission. This after my driveline was replaced last week! I'm a bit frosted about that!

I took it to a different mechanic yesterday (Medi's in Concord, CA), he road tested it with me then hoisted it up, had his employee run the trans to 17 and 27 mph (loudest points) while we were under the car. When I placed my hand on the transmission, it was vibrating like the dickens, most at the above speeds. How much vibration is normal in a transmission? When it was engaged and starting off you could hear a sort of a soft grind until the driveline was spinning.

The fluid was checked, he had to stick his whole finger in to get to the fluid so it was very low. Drained transmission, fluid looked very dark with a bad smell. No metal parts or shavings in the pan. Replaced the fluid with 1 qt. Mercedes differencial oil and 1 qt+ with castrol ATF fluid. It shifts MUCH easier through the gears but still has the buzz and vibration in the car. Mechanic said to get rid of the noise/vibration the trans would need to be replaced but the fluid change would keep me on the road awhile longer if the noise/vibration didn't bother me (it does).

Questions - Could the problems be caused not by the transmission but the clutch? Transmissions seem to be indestructible right? What would a new, rebuilt or used tranny cost and to put in? While the tranny is out should I have a complete clutch job done? Don't know what bearings, etc. need to be replaced in that job? Could any easy items in the tranny be fixed/replaced without replacing the tranny that would cure the ill?

Thanks, Tim