Hello all! I'm new here and already found much useful information using the search mode. But I couldn't find anything on this... I have '89 300E 145kmis. I bought the car for wifey w/ 122kmis and has had this problem since ever. There is a cyclical vibration when driving at highway speed. You can actually feel it course from one side of the car to the other. I have balanced, re-balance, replaced tires. I have MB wider wheels and one size bigger tire, but also does it with four new snowtires and new steel wheels. Can driveshaft or differential u-joints cause this? The symptom does increase in amplitude and frequency related to road speed. Does this automatic tranny use planetary gears that may be worn? Could it be a torque converter? If anyone has had & corrected this problem, I'd sure like to hear about it .