Well, yesterday I put the car on a lift and looked under it real close. I can grab the driveshaft with both hands and twist it back and forth and there is a little play but I think all of it is inside the transmission. I can push up and down and there is a very slight play felt but I think it would not cause any vibration but not sure. The flex disk look and feel tight. There is a long aluminum pan between the exhaust pipe and the driveshaft and I did not remove it to look above, but everything feels tight. The size of the shaft looks to be bigger in the back than in the front so there is some kind of transition or coupling above the pan somewhere.

I stated that the dealer replaced the engine mounts and the transmission mount. I looked at the transmission mount and it looks like there is slack between the rubber part in the middle and the rubber that surrounds it. Is this normal or should the rear transmission mount be tight between the two rubber pieces?

I still think it is a tire problem. If a tire is out of round or bad, would it show up on a balancing machine?

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1995 S-350
370K + SOLD
1952 220B Cabriolet
39K kilometers + SOLD
1998 E300D
310K +
2012 E350 BlueTec
120K