Vacuum Modulator Pressure setting
 

I'm working on removing vacuum issues and I've got the proper curve all through the system. My Question is now what should I be reading when I test the vacuum line to the transmission. I don't want to fiddle too much with the transmission modulator valve (already turned it 4 notches CW in an attempt to solve the slip experienced on all changes) without knowing what I should be reading when I hook up a mityvac.

So, what should I be looking for? holding vacuum or a slow leak, or what?

Also It's Clockwize for harder shifts and CCW for softer right?


(FYI I do have a transmission fluid leak, but keeping the level topped up.)

You can't really set the modulator without a proper pressure gauge hooked up to the service port on the transmission. The modulator adjustment isn't really that sensitive. I've found that a full turn will only result in a small pressure change. Unfortunately, I don't remember the specifics. It's been too long.

It's really easy to make a pressure gauge. I grabbed an 8mm banjo bolt from the salvage yard, about 8 feet of plastic tubing from the Home Depot, and a 100psi gauge off Ebay. Total cost under 15 bucks.

There used to be an excellent write-up out on the web on how to adjust the vacuum source to the modulator. A google or a search here should find it. If i remember right, it was written by Steve Brotherton.

Found it:
http://www.continentalimports.com/ser_ic20242.html