I purchase a 92 300E about 28 months ago and have always been very aware of how this car seems to shift really hard. I can manually shift causing the RPM's to go higher and this makes a much smoother shift. It seems also that the shift points are too low, but this may not be causing the problem, just making it worse.
Vacuum? I don't know where to begin. I have also played a little with the linkage at the air intake but it's tedious to just guess and test drive over and over. HELP!!