OK I installed a Pac/brake PRXB on a 97 12v egr motor with 60# springs ,it has a goarend vb with 2-4 lockup DTT 89% converter ,3.54 rear. system has no leaks and I have DBL checked ,brake is working lockup is working .But the brake has little to no hold back with out a trailer. I have this brake on 2 other trucks and they work great ,But this is the only AUTO I have a brake on and it stinksany body know why?? are autos this bad?.
Thanks R

 

Is the TC locking up and staying locked down to 20 or 25 mph? If not, the brake will be ineffective.

Dan