I have a 1993 300E with the same problem. 92,000 miles. The problem exhibits itself mainly for the first 30 minutes or so. After the car warms up it is less noticeable. It doesn't happen with shift point over 2500 - 3000 rpm. Just on lower rpm shifts. All other shifts are very smooth at any rpm. I've also noticed moving my car around in my driveway that it can clunk when moving from drive to reverse or vice vesa. Don't know if these issues are related.