Yellow Bullet Forums banner

4L80E trans brake issues

287 Views 3 Replies 2 Participants Last post by  Hutch
New here. Having problems with my newly installed trans brake valvebody. Here’s the back story. A year ago I had a friends father( he has been building for 30+ years and was working for a well known performance builder at the time)build me a full manual 4L80E for my big block camaro. It might have 1000 miles on it. At the time I couldn’t afford a brake. Trans worked flawless. So this spring I finally was able to buy a billet brake valve body. I pulled the trans back out and per the instructions he pulled it apart to drill the relief hole in the direct drum. Everything in the trans was perfect and still looked now. Get back together and I put it back in the car. So never having a brake before I followed all the instructions. Fill it up(yes the dipstick is verified correct) and try it out and the brake won’t hold past 2800 rpm and reverse isn’t there unless you blip the gas. Go buy a pressure tester and all shifter positions are at 210 lbs except reverse which is barely at 90. Valvebody builder says there has to be a leak in the direct drum. Tells me to air check it through the pressure port with the manual valve in reverse. I can hear gurgling and a piston apply. Builder says he’s confident the rings and piston are good. Running out of options and looking for ideas to what could be wrong. Sick summer is less than 2 weeks away and I’m gonna be screwed soon if we can’t get this thing working. Please help lol
1 - 4 of 4 Posts
Does it have engine braking? Is reverse and transbrake pressure low? Press in 3rd is ok?

So Micheal from ATD reached out to me. He told me to pull it and they would dyno it to find the problem. Turns out they ended up tearing the whole trans down to find I got screwed by the builder. The reverse band wasn’t replaced and the the reaction carrier was junk. It had multiple other issues that had nothing to do with their valvebody. They went out of their way to fix all the problems that shouldn’t have been there with a fresh rebuild. So I have to give a huge shout out to Charlie and Micheal from ATD for no only fixing my trans but getting me going in 24 hours and making all the fucked up butcher parts and setup right. I can’t thank them enough for making this happen because I would have been done for sick summer. They had no stake in what was all wrong and they sure didn’t have to fix it right away soon as the problems were found.
  • Like
Reactions: 1
Glad you got it all fixed up. 👍

1 - 4 of 4 Posts