interesting observation in 1995 E300D
 

I was busy fixing up stuff in my E300D like the idle control issue, condenser fan resistor, blower motor etc..

I joined the red vacuum line that leads to the right fender to the vacuum system, it was previously cut by the PO and I then had blocked off the cut vacuum line to prevent leaks, I joined the line, with a piece of rubber vacuum tubing and new clear MB plastic vacuum line. The shift behaviour has improved dramatically over the entire range, the HVAC system is also faster to respond.

I dont know how much the idle control issue resolved this but I believe the shift quality has improved

That can only help. Those tranny's just don't seem to be as robust as earlier flavors. And that OM606 works best when you are shifting correctly. Such a smooth combo!! :)

When you say improved do you mean firmer or softer shifts

by improved I mean the cold shifts are softer now and the warm temperature shifts are very torquey, they were slightly sloppy before - and the sloppiness was noted specially when the transmission shifted from 2-3