billybatty

New to the site, excellent info and posters. I have an easy question, but I know it has been the source of argument, but here it is. The sonnax servo check mounted on the 3rd accumulator port. Install the sonnax part or no?

mrvedit

A assume you are referring to the Sonnax "Servo Release Check Valve".

I have installed it on the transmissions I have rebuilt, but cannot say I feel any difference in the 2-3 or 3-2 shifts. I believe some builders leave it out, but drill the 3rd feel hole to .120 anyway. I know many performance builder do use it. Also Sonnax is creating ever more performance parts for the 4L60E and I trust their research.

If you do install it, I suggest first tapping it with a 5/16 tap so that you can pull it out if needed.

Also, remember to drill the Orifice to .120 (or 1/8") if you are using a corvette or performance servo. Since the initial hole is quite small, I recommend drilling the hole in two steps.
Blow out all the metal shavings.
Then thread a 5/16" bolt into it and test the fit; if loose, install the supplied o-ring.

billybatty

Yes that's the valve I'm talking about. The reason I'm thinking about putting it in is to guard against the dreaded "2-3 flare". I will be keeping the 3-4 stack tight, around .020, I guess the question is is it "insurance"for my 3-4 stack. Nice idea on tapping it for future removal, too bad the 3rd accumulator wasnt tapped, which is what I had to do to get it out.