Hi Marc,

I had a similar experience with a 1982 240D with manual transmission. The problem turned out to be the collar on the back of the transmission that mates to the flex disc had rounded out bolt holes. The problem was spotted by an employee of a local shop with a sharp eye and a keen sense of how things should look. They replaced the collar with a used piece they had on hand. No problems since.

Marvin Kraft
Green Valley, AZ