Does anyone have this problem i have tried to find out what is the problem, please help if you have something in mind.

 

What do you mean by, "second gear pressurised on 3rd" ?

 

Hello,
I mean that when 2nd gear shifts its OK but after that when the 3rd gear shifts pressure in line of second do not go away it keeps it (100psi or little more). and this makes 3rd shift very odd and tranny makes heat very much because 2nd is on at 3rd. It seems like exhaust of second is jamming or something else but dont know what.

 

2nd and 3rd fluids are closest to each other in the servo -- 3rd gear fluid pushes the servo backwards to release it and thus release the band -- you may have some bad servo seals.... but then again, could have some sticking valves in the valve body as well, or a split seperator plate gasket, I would have to check the diagrams... there are probably more than a handfull of things that can cause this symptom. Tough to diagnose over the internet.

 

i have mounted sonnax check valve to system but i'm not sure is that the problem. I have checked every valve those are moving OK. separator plate is new from transgo. it is very strange because its not even try to release pressure when 3rd comes in.

 

it doesn't release 2nd pressure, it overcomes it when 3rd comes on. The 2nd valve stays shifted until you go back to 1st gear. it could very well be the sonnax check valve -- the one that goes up in the case from the valve body side?? I would call sonnax and see what they say to do...but if you have easy access, it might be a good idea to pull the servo and doublecheck all the o-rings and teflon seals.... did you put the return spring around the servo pin before you installed the servo assy?? it has to be there.

 

I take out servo and check all seals and springs those are OK and i also check band clearence. Servo is corvette style aftermarket model. I have had this tranny before in astro van and it worked well long time but then 3rd burn out and i repair it to this project and found quite many worn parts but those i put new ones. It takes 2nd of when i slow down or reverse or neutral.

 

what?

 

I mean that if i slow down enough speed it will take 2nd gear of normally (1st gear) like it should so pressure release normally. thats why i wonder is there some mod too much so that pressure is not released now with this new check valve. almoust all of these transgo shift kit modifications has been in this tranny allready and it has worked normally before full repair

 

ok, that is correct and how it should work. FWIW, I have overhauled hundreds of these over the last 20 years and have had only ONE check valve problem, where it needed replaced. I am suspecting something with your sonnax check valve -- did it get installed all the way in? or maybe too far in? I have never used the sonnax, I just replaced the one I needed to with the GM part.

Those teflon seals are REALLY easy to cut when installing, -- the other thing to check is that the 4th piston in the servo is installed correctly, the longer center part has to face towards the dent in the servo cover(pointing out away from the transmission), not towards the servo itself, that will give you some bad band problems (sticking on and such) it's really easy to get in backwards.

 

4th piston is tall **** to outside of tranny. Teflon seals on pin are OK. I put new check valve (original) and this sonnax valve comes after that one. Sonnax instructions told that original valve must be there also.

 

I meant the teflon seals on the 4th piston and the 2nd piston

 

those seals are OK checked. do you know what valve or system is releasing this pressure on this 2nd gear just thinking that if i have too much pressure on some valve.

 

3rd apply fluid seats the check ball to push the servo backwards to release the band. IF the check ball doesn't seat, it may be venting the fluid, causing it to not build pressure to release the servo, might have a piece of trash stuck in it, or the ball itself is missing....

I'm not sure pics of the pages will be big enough to read if I post them, but let me know if you want me to try

 

reading further, you might have the 3-2 control valve stuck....

 

It is readable many thanks for these informations i try to figure out.