99 300m with a vibration

I have 165,000 mile on my 300m. Just bought the car and was told it had a transmission problem. It's a vibration at 35 to 50 . Worse under acceleration and on a right hand corner. I perfomed a quick inspection of the motor mounts and axels. All looks good. I've been repairing cars for 25 years and consider myself very good at transmission diagnostics. It's not the transmission. I don't want to throw parts at the car just yet. It acts like a inner cv joint. Does any body know of any common problems??

The best thing you can do related to a 300M is to join the
300M club at 300Mclub.org. That is where I get all my information and it is a most helpful group. If you join for $15/yr. you gain access to the knowledgebase and can go to club meets, etc. Just a great group of very helpful and knowledgeable folks who only care about M's.