pressure relief valve

[stovebolt 34]

Sure it's been covered before so I hope I don't get tarred and feathered for asking . . . . .

Put .500 main & .296 reverse boost valves in my 200-4r last year with the green spring . Small instruction sheet appears straight out of Transgo . Says to grind the 2nd land off the valve "it's not fussy ".

Is this mainly for 700-4r's ? I did NOT do this modification . Do it or not and why ??

Thanks . . . . Gordon

 

[stovebolt 34]

Sorry . . . I meant pressure regulator valve . . . .

 

[Steve V]

Don't grind it off just two flats on each side,this is supposed to allow "full time" convertor lube but not hurt flow too much,also help with PR buzz. This is what I was taught and maybe someone more knowledge will correct me if I am wrong. Have done several this way with no adverse affects that I can tell.

 

[mikestertwo]

I would not grind off the second land. It will increase the charge pressure inside the converter forcing it forward. It may result in a wiped thrust bearing in the motor.

 

[stovebolt 34]

Thanks Guys , Would just grinding a couple small flats make the converter produce less heat when out of lockup ?

Would there be more pressure on your cooler hoses ?

I was just poking around and ran across a truck forum . Guy on there says "WE" taught GM how to do it -- the PR Valve mod . Says GM started doing it in 1992 on the 4L60-E . Says try it you will like it . Says you will feel the difference . More low & mid range torque , he says . Keeping in mind he's talking about a 700-4r .

Interesting . . . . . .

 

[Steve V]

Grind the 2 flats don't go crazy...it will not ruin the thrust bearing..unless you go crazy.
IIRC 700 pump is very similar to the 200 uses many of the same parts including PR valve set up.

 

[stovebolt 34]

Thanks for the info . How about a AC Delco part number for the valve ? I would kind of like to have a spare if I decide to do the 2 flats , just in case .

 

[Steve V]

valve is discontinued...700 uses the same one any tran shop should have plenty.

 

[CliffyC]

Mikestertwo is right. Someone ground the land off the pressure valve in my trans before I got the car. With rebuilt motor only took a couple hard launches and not only did it wipe the thrust bearing took the crank too. I now keep the valve on my dresser as a reminder of what not to do!

 

[stovebolt 34]

Yeah , Kinda got me to thinkin I better leave well enough alone .

 

[CliffyC]

see pic

 

[stovebolt 34]

Makes me wonder what Transgo was thinking . . . . " Its not Fussy "

 

[77 cruiser]

I used one like that, never had thrust bearing problems, but I did trash a converter.
I can't remember the pump I got from Chris had that mod done or not.