So, after reading through posts for 2 hours to try and understand my vacuum control valve, decided to take it off car and take it apart.

Once on my bench, it was very easy to see how the little bugger works, and I could hook up my Mityvac and adj inHg on my bench.

It seems to me (please check me if I'm wrong here, Sandy) that the only way to adjust the vacuum (and, thus, how much vac gets to trans for shifting) is to adj the linkage going down to inj pump.

Making the linkage shorter will increase the vacuum and longer will decrease the vac.

So, in my situation, I've got tons of vac going to the VCV (when unplugged). Once VCV is plugged back in, at idle its controlling vac to 10 inHg and once I rev up motor it falls right off to Zero. So, if I shorten the linkage, then I'll have more vac at idle and thus more vac as I accelerate, which will then give the trans the vac it needs to shift smooth! Whew!!

Do I have that right?

I just made mine shorter today actually, when you make it shorter you make it start bleeding vacuum sooner. Make yours longer to make your shifts happen with less throttle travel and smoother. and yes you just change the linkage.

Remember the furthur the arm moves the the more it bleeds and the later and firmer your shifts will be. so if your car is making less than stock power (and your foot is in the floor) you will have late firm shifts, modifying the linkage will just make up for a engine related power issue.

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1996 s10 zr2 with a 6.5 turbo diesel
1996 c2500 suburban with a 6.5 turbo diesel
1981 300sd with a turbo 617
Monte carlo figure 8 car