Make sure you have a low band apply. (all transbrakes should so if you go that route you should be fine) I bet ya a nickel it hurt the sprag in the burn out,do you use low gear for the burn out?
I currently dont have a trans brake, but I do start my burn outs in first, but I jump to second and drive as soon as I can. I dont rev up and down in the burn out box and always try to spin through the box so as not to hurt the trans...not sure why I killed this one.