TransBrake Problem Need Help

[andybyrd]

OK, I took it out to the track today. the first run transbrake @ 3600 did good but it seemed to need more so I put a 3800 chip in it did good again but seemed like 4000 would do the trick. BUT it would not release @ 4000 so I went back to 3800 and it would'nt release there either now. when I droped the RPM's Down to 3400 it would grab and run great. what could this be. please help
Andy Byrd

[chevyfireball]

When was the trans last rebuilt? Is the transbrake solenoid operating ok if you engage it without the engine running? It should click fairly loudly.

[hammertime]

Will it realse just sitting there with the car not running, hit the button and see if you can hear it realse if not its not the chip issue.

[johnracer]

When you say it wouldn't release, do you mean when you release the button it just sit's there, or will the transbrake not hold the car at that rpm?

[andybyrd]

I'LL Answer all replys, it's a powerglide in a 2500 # car w/665 H/P 514 gear and I don't know how old it is. its probly got 4 seasons on it. it does not slip in anyway it shifts perfect. Ive been foot braking with no problems.
now the chip part is working fine when I change chips and hold the button down it runs up to what ever rpm chip I put in it,

now the silinoid is clicking in and out when I hit the button and it dosnt seem to be sticking.
to me it seems like when i have to much RPM it want release when the rpm is low it releases no problem.

when I release the butten at high rpm 4000 it just sets there at 4000 it releases and jumps off when I let the RPM down.
Thanks Andy

[BEAST477]

Check and make sure it's not in your microswitch itself. I just had this problem with my new transbrake switch. Would set the transbrake but wouldn't release. It was a bad solder in the switch itself. Disconnect your wires coming from your transbrake switch and test with an ohm meter. Wiggle the wires while checking and see if it changes. Just a thought.

[andybyrd]

I have a new switch I'm gonna hook it up. but just a thought here. could the solenoid spring be weak and not releasing under to much fluid pressure. and also can I take the valve body out and clean it up good, maybe something is just sticking, I don't know all this transbrake stuff is all new to me. but it sure felt better than the foot brake so I'm gonna try and fix it. I just don't want to spend any unnessasary Money if possible so I could sure use all yalls help on this.
Thanks Andy

[johnracer]

So it stays on the 2-step and doesn't release at higher rpm. Maybe something's backfeeding into the trans brake circuit. Maybe that diode was someone's answer to the problem........could be a ground problem. Definately strange

[onedragracer]

Are you running a delay box of any kind. You might have accidentally rolled some numbers in it. That would explain why its not releasing.

[dparker]

Trace your trans brake wire. I bet its tied into a RPM actived switch, either in the delay box, MSD box, or 2 step.

[andybyrd]

let me back up and tell the whole story, I bought the car from a man here on RJ and I can't find his # anywhere. now the car is in great shape, he did run a delay box but he had unhooked it all and got rid of it. I do have all the wiring spec.s on the car and the trans brake was run through the delay with the diode. but now without the delay box the transbrake would not work through the 2 step so I took the diode out and now it does work with the chip. now my biggest question is do you all think it is the valve body or some kind of electical problem. let me try and explain mor clearly the problem. the first time I tryed it. it would not work off the chip in the 2 step so I get to the tree and puss the button WOT 5500 RPM release the button nothing just set there at 5500 rpm so I release the gas peddle and it released @ lower RPM and stood up and went perfect down the track, Trans OK. so I go home run all the wires to figure the 2 step problem out and thats when I found the Diode between the button and the 2 step took it out and the 2 step now works perfect and also reverse works perfect. when you push the button so the Diode wasnt for the reverse. so now I go back to the track I put in the 3600 chip it worked perfect. then I put in yhe 3800 chip in and it worked perfect. so then I put the 4000 chip in and it just set there at 4000 rpm when I released the button so I let off the peddle again and it took off and ran perfect. so I thought it was a RPM problem so I put the 3800 back in and it wouldnt release at 3800 untill I got off the gas peddle, so I took it home. so I could ask all of yall if yall had ever heard of one doing this and what could it be.. If the valve body was bad would the trans still work perfect with foot braking, because I can foot brake and everything is perfect. but I would like to figure this out. And yall have been and are a Great help.

Thanks to all for your replys, Andy Byrd

[curtisreed]

Andy,
I don't think it is electrical at all. I wonder if it is some kind of pressure issue when you get to a high enough rpm it makes a pressure or possibly a binding issue like the servo or something. I don't have an intimate knowledge of trannys to diagnose it, but I still don't think it is electrical or I believe it would act the same at a lower rpm.

Curtis

[andybyrd]

Curtis. thank you much. I've been leaning that way also. a presure problem not letting it release. I thought with all the Talent and experince here someone would have heard of this before and know the problem. but as my luck would have it I'm probably the first guy that has ever had this problem. well I'm gonna take it out and see if a good cleaning and fluid change may help. I hope but probably not. But I will let yall know so we may be able to help someone else if this ever comes up again. but I'm still watching the post so if anyone can point me in the right direction I'm here.
Thanks Andy

[johnracer]

If it stays on the 2-step after you release the button, it has to be electrical. No internal tranny problem will cause that. dparker may be correct. I'd trace the transbrake wire all the way back to it's power source. I bet you'll find something there.......

[andybyrd]

well I'm gonna try the electrical thing first and rewire my new switch in and see what happens. I don't know enough about the way the valves in the tranny works so I can't say anything about that. but I will try the least expencive way first. I.ve already bought the new switch so I'm gonna change it now.
Thanks Guys,
Andy

[curtisreed]

I missed that it stays at 4000 if that is the chip installed, I thought the brake just wouldn't release. I hope it is the switch or wiring. Easiest thing to fix.

Curtis

[onedragracer]

Andy, is this a pro tree transbrake or a full tree brake, Do you have to push the transbrake button to back up?

[andybyrd]

yes sir I do have to push the button to back up.
Andy

[dparker]

I think a new solenoid will fix your problem.

[andybyrd]

Thanks guys, I ordered a new solenoid yesterday and took the old one out today and I put a new switch in also. the old solenoid seemed to have trans fluid in it like it had a bad seal around the pin that pushes the little rod in, so I hope thats it. I will try it out saturday and let you all know the out come, Thanks Again for all yalls Help,
Andy Byrd

[andybyrd]

well I changed the Solenoid and the switch and @ 4000 rpm It came out great twice. then it would stick a little. so now I'm going to change the return spring I think it may be getting weak when it heats up. I'll keep yall posted.
Thanks Andy Byrd

[onedragracer]

well I changed the Solenoid and the switch and @ 4000 rpm It came out great twice. then it would stick a little. so now I'm going to change the return spring I think it may be getting weak when it heats up. I'll keep yall posted.
Thanks Andy Byrd
Andy, if you are running a protree brake, they do not have a return spring behind the solenoid plunger valve, If one is in there take it out, that is your problem.

[andybyrd]

wow now I'm lost. how can you tell if it's a pro tree and what is the Difference Please. this one has a about a 1/2 spring that goes around the valve. and I thought that was what pushed the valve back out when you released the button. But I know nothing about these things but am trying to learn.
How can I tell what Kind of Brake it is, you do have to use the button for reverse.
Thanks Andy

[johnracer]

If you have to push the buttom for reverse, it's a pro brake. I've seen some that used a spring, and some that don't. I did a tranny for a friend this winter and it a pro brake with a spring. I think it was an ATI brake. Fluid pressure moves the valve if there's no spring. I really don't think the spring would hurt anything regardless as long as it doesn't bind up the valve..........
Johnny

[andybyrd]

ok so I could have a pressure problem, if it has the spring is that what's moving the valve when I release the button. if the pressure was low would it effect the rest of the tranny, because the tranny on the foot break is perfect.. Thanks for all yalls replys
Andy Byrd

[dparker]

Andy make sure the plunger is in the right direction.

[andybyrd]

Thanks Mr. Parker I'm sure that's right, well I put it back in the way it came out anyway. but yea from looking at pictures of others I think its right. I did not know that fluid preasure was what released the valve. I thought it was the spring. if fluid was what released the valve then on mine when you are just testing the solenoid and you hit the button it would not release if the car is not running without the spring. so I'm gonna buy a new spring and try that first. but The trans does have some runs on it so I'm sure it needs to be gone through. and this will be my first Trans job but I believe I'm gonna do this one myself and see if I'm as smart as I think I am. if you guys have any Advise I would sure listen to everyone on this.
THANKS Andy

[johnracer]

Glides are super simple. I'm sure you can do it! My advice, get a book. JW has a nice one on how to build a race glide. I still use mine. It looks like crap, but has a bunch of useful info and step by step instructions.......

On another note, when it hangs up, is it still on the 2-step or does it go up on the converter and not move? Sorry, I'm still stuck on the electrical side of this deal......I know, it's annoying, but when I get something stuck in my head, sometimes you have to whack me with a stick to get it out..........
Johnny

[andybyrd]

that's ok Jonnny, I'm like that myself. I get into something and its hard to get away untill I figure it out. I just don't want to beat yall to death with this thing. ok to answer the question. the first run after I replaced all the wires ,the switch the solenoid and the screen and fluid. It was perfect, it realeased like it should. one hour latter 2nd run. I went up on the 2 step to my 4000 rpm chip it sat @ 4000 untill it released about 1/2 second after I released the button. then it stood up and ran great. Hey I'm open for any and all help. the only thing I did'nt do was replace the return spring. and now it has me thinking that when the spring gets hot it gets weak. but now I'm learning that some pro brakes have a spring and some don't, mine does. my lack of expierence on this has me wandering if you had a brake without the spring you could not check to see if it was comming out with out the motor running if it was working off pressure because youd have no pressure, [yes or no] I'm just trying to learn here. and thanks to all you guys I have been getting better. yall have got me from 6.20 in the 1/8 to 6.10 in one week I can't wait to get to the 5.80 class, because 6.10 aint making me shake at the end of the track no more,
Thanks Andy

[johnracer]

You are correct about the no-spring brakes. In fact, the car has to be running and in low or reverse for the valve to move back out.

It should have come up on the converter when you released the button, regardless of whether or not the brake released. I think you said it came up to 5000+ with no chip in the 2-step. As depressing as it sounds, I still think you have an electrical problem instead of a tranny problem. Have you traced the tranny brake wire all the way to it's power source? Since the car had a delay box in it at one time, there may be something else in the circuit......you should have power coming to the button, and wire from button to trans. The 2-step should be spliced into the wire going to the trans. That's it, nothing else should be hooked to it......

[andybyrd]

Well I ran all the wires again and they are like you say they should be. what I did just to see if it is a weak spring I put a very simple outside return spring on it and now when I hit the button and release it it releases NOW so I'm going to try that Saturday. But If the pro brake is released buy fluid preasure and I don't have enough preasure to release it without the spring. then even when I release it with a spring it may be slow to react. do to lack of fluid preasure would that be true or false, Thanks guys this forum is very informative and great learning place,
Andy Byrd

[dparker]

Well I ran all the wires again and they are like you say they should be. what I did just to see if it is a weak spring I put a very simple outside return spring on it and now when I hit the button and release it it releases NOW so I'm going to try that Saturday. But If the pro brake is released buy fluid preasure and I don't have enough preasure to release it without the spring. then even when I release it with a spring it may be slow to react. do to lack of fluid preasure would that be true or false, Thanks guys this forum is very informative and great learning place,
Andy Byrd

Andy if you didn't have at least 150lb of pressure your clutches would slip. You could be a little lower than than you should. But in my opinion your plunger or your valve body is sticking.
You can check your pressure by removing the plug on your sirvo cover, and putting a guage on it. Should be at least 190lb. You may burn up your solenoid by using the spring on the outside.

[andybyrd]

Thank you Mr Parker I never thought of burning up the solenoid but I see what you mean. so what I did just to check for sticking was. I put just enough spring tension on it to come back out to prevent any sticking. if it gives me 3 perfect launch's I'm taking the out side spring off and try that, and I'll post yall the results tomorrow Night, and again Thanks to all yall on here yall are great,
Andy Byrd

[dparker]

Well Andy, just looking for a status report. How did your trans do?

[andybyrd]

Hey, Guys sorry for not replying back sooner. I've been out of town. But I'm going racing this Saturday and I will let you know what Happens. If it don't work this time its comming out. I can set in my drive way and hit the button at low rpm's and release it and it works perfect everytime but I'll have to see it work @4000 rpm before I believe its fixed. I'll post it Sunday.
Thanks for asking Dean
Andy.

[andybyrd]

Ok. it went perfect 3 times. 4th time Transbrake completely gone no reverse and when I went to the tree and push the button and floored it. it took off like there was brake at all. and the button is going in and out so its comming out today for a redo. Thank all you guys for all yalls Help
Andy

[andybyrd]

well guys just to keep you informed for all the help you all gave me .
I decided not to pull the trans out because when I got home it worked perfect. so I bought another solenoid { coan } and put a new spring in side over the valve and it works perfect now. thanks guys for all yalls help.
Andy

[gsjohnny]

i would like some help on a similar isue with my p/g.
we just got the 2nd car going and everything was working. t/brk, launch AND reverse. next day, no t/b or rev. pulled apart the solenoid, it was fried. bought a new one. installed it. on t/b, the car creeps foward and still no reverse. any ideas?

thanks
john

[andybyrd]

When you pull the solenoid take a little magnet and see if the valve will come out. then see if it has a spring around it or in it . coans brake valve has a spring in the back of it and mine has a spring around it. I heard here that some don't have springs they work off presure. I.m not very smart on trannys but I will try to figure them out. clean off your valve when you take it out and check the spring tension. it sounds like my problem. the same thing happened to me last week @ a race just a little reverse and no brake. when I hit the Brake button and floored it and we went red and flew down the track. that was the 2nd solenoid. so I put the new coan in it and now it works perfect. I hope this will help you I know how agravating this can be. Good Luck
Andy Byrd

[gsjohnny]

original was the old style tci. replaced it with the new style. i hate changes. will put it apart and see what kind of magic is in there.

thanks

[sommersracing]

original was the old style tci. replaced it with the new style. i hate changes. will put it apart and see what kind of magic is in there.

thanks

Not all T-brake solenoids are the same, you need to measure them.

[gsjohnny]

say it aint so. i going to take up basket weaving.

ok. if its too short or too long, how do i make up the adjustment?

[gsjohnny]

new solenoid was 1/8 shorter. i made a spacer to make up the difference. it works!!! now the buick can race. and i will give up basketweaving now.
thanks for the help. you guys are great. :D :D

[3758]

the brake pressure is maxed out at around 1800 rpm so that that won't cuase the problem it's either elect. or the solinoid. The only other thing I can think of in the trans that could be causing the problem would be in the release springs in the rev piston. Is it a probrake? do you hane to push down the brake botton to back up?

[3758]

Pressure doesn't release the brake the pressure is dumped when you release the button. when you press the button both low gear band and reverse clutches are ingaged. If the brake holds you on the line theres no pressure problem

[3758]

If you or someone else replaced they valve body they may have put in a probrake valve body where there was orianally a full tree brake. A probrake requires different hole be drilled to dump the fluid. Again pressure has nothing to do with the release the solinoid is a elictro magnet. There is no advantage using a pro brake unless you are runnig on a protree.

[clwarters]

i to have a problem with a 400 turbo trans brake first gear , second gear will take your breath then third will freek you out it will go hard 30 feet then bind up like trans brake trying to engage i un hooked wire to t/b still will do it ?