Originally Posted by Junkman

My 85SD had a 2-3 flare and a 3-4 flare (722.303 trans, green vacuum modulator). I removed excess vacuum systems so that they are out of the discussion. My 3-2 valves on the valve cover are gone per another thread as is the EGR.

I have 22' of vacuum out of the pump. I set the VCV per the FSM and the vacuum modulator to 42" per one of the transmission manuals. The modulator seems to hold vacuum. My gauge fitting seems flaky ie holding one minute then leaking if I move the hose. I've got some plastic adaptors being glued to make sure they aren't leaking.

The 3-4 flare is still there. This seems to be the case regardless of how I set the VCV.

So: If my vacuum modulator holds vacuum, is it necessarily good?

What effect is higher or lower VCV settings supposed to have on shifting?

What effect does changing Vacuum modulator pressure have? I increased vacuum Modulator from 35 to 42#. Should I go a little higher?