Im actually having the same question, I have a 1985 300sd california edition (i know) and i had a vacuum leak in my climate control which made my tranny shift horrible. So i plugged the line going to the cc system and now my tranny gets much higher vacuum around 16". From what Iv read this is a little higher and should be a little closer to 8". I got this figure from post #68.
It's CRITICAL... how you set your transmission's vacuum system on your diesel MBZ...
I went to the VCV, removed the dome and it was actually like a bolt rather than a screw. I tried to adjust this by turning it ever so slightly and it changed the idle rpm setting and the car immediately was idling at a higher rate. This made the vacuum drop to about 11" but the idle was wayy too high.
What am I doing wrong? I thought this might have been controlled by the alda not the VCV? How can i get my vacuum system to leak a little bit without changing the way my car idles?
p.s. My car kinda smokes a lot i was wondering if i could lean it out a little without adverse affects on power it seems like a lot of fuel isnt burning right