I just put in a Th400 mrvb w/brake (BTE) i had locally built here. I ran the car through the gears quite a bit on jack stands to ensure everything was working correctly and no leaks. However my first trip up the street, I shifted to second...then around 45mph I shifted to 3rd...3 seconds later the rearend locked up completely and i layed down a nice set of skid marks until the car came to a stop. It wasn't too bad at 45mph but at 130, it would have been a different story. Sometimes it acts like the brake is activated in 3rd and won't move, hence why the tires locked up, other times it works ok. When it's working correctly, the brake only works in 1st and when i put the shifter in reverse, the car backs up as it should.....when it's not working correctly, the brake works in all gears and i have to use the brake button to get the car to back up. I don't understand autos enough to know what's happening inside but i guess something is leaking pressure into the reverse side of things?

Either way the tranny is coming back out. I don't want to take any chances.
The builder said he had just put together another transmission with the same valve body and it had the same problem so he must have gotten a bad batch of valve bodies.
This guy builds majority of the transmissions around here so i don't doubt his abilities but my main question is how can I ensure this will never happen again? Don't run a brake?
Locking up in 1st gear or just plain slipping is one thing, but locking up in 3rd will always be in the back of my mind and i would rather put the 6-speed back in then have to worry about it.
BTW I'm using a B&M quicksilver racheting shifter and from all i can tell it's adjusted correctly based on the instructions....but what would be the symptoms if it wasn't correctly adjusted? How close do i have to be?

Thanks
-Jarrod

 

when its working correctly you should have to use the brake button to get it to go in reverse..

 

I was told this T-brake does not require that...I know some of them do and some don't. I think the ones that use the button have severely more line pressure and therefore are not good on the street?

 

Ok i called BTE, they said their valve body does not require me to use the button to back up.
They said their transmission builder is out today but should be back tomorrow so maybe he can explain what happened. Has anyone ever heard of a th400/350 locking up like this in high gear?
Thanks

 

WoW thats scary thinking of it locking up at a really high speed hope ya get it fixed

 

Damn, don't everybody reply at once!!!!!!

Ok so after doing some research, i am fairly certain a check ball was left out of the reverse accumulator which would cause the exact problems i am having. I can't believe I almost trashed my ride for a little steel ball. It kind of scares me that the tranny guy didn't install it...wonder what else he didn't do....

My valve body isn't the same one as this but same idea: scroll down to second page:
http://www.artcarr.com/instructions/14004.pdf

 

sorry to hear that Rice Peter. I'd find a better builder next time. fo real

 

Well he has built probably 30% of the trannys for the cars at richmond dragway...guess he was having a bad day. But i still don't know for sure if that is the problem so i will give the guy the benefit of the doubt until I pull it apart.

 

Chuck and I were discussing your situation today. The only thing that made any sense is that the rear band was coming on for some reason. Your theory sounds good to me. I always make sure to have the proper directions when doing a break. There are a few different types and can be tricky if you do not pay attention to what you are doing. I also make sure to go over the directions more tan one time as well to make sure that I have not left a step out. It also states in most directions that if misassembled damaged may occur. Damn good thing you and your ride are still in one piece. Good luck man. Vince

 

Thanks for the input Vince. While i've got your attention...is this style valve body not safe to run? I have read about others that do not use the check ball but i guess are machined differently to eliminate this from happening? If there is a chance this could happen again i will switch to another VB.

Thanks again

 

DOES THIS HAPPEN EVERY TIME YOU SHIFT TO 3rd/Drive, if so i have seen this problem occur when the foward drum sprag was put on backwards

 

Thanks for your input....any help is much appreciated.
I drove the car last night and it worked perfectly....the tranny takes about 2 seconds after i move the shifter to reverse to actually click into reverse, but it works. I only got up to about 25mph in 3rd but all four times i tried it, it worked like it should. I rode up and down my road about 3 miles in 3rd and all good....but as i said, i don't trust it to go 130mph. Damn this car!
I wonder if the check ball in the VB was just sticking or has some trash around it?

 

not likely on the sticking, if its a steel check ball. i'd say you have a fluid bleed over problem like the rest of these guys are telling you. in my opinion i would definately take it back out of the car and have your trans. guy take a look at it. i would make him tear it completely down and make sure everything is ok on the inside as well. make sure he didn't over tighten the Center support bolt and crack the case. they are only supposed to be torqed to 37ft lbs.