TH400 1st, reverse and trans brake problem

I'm a bit confused on whats going on with my TH400 trans. I only went on a power run or two on the street. never built up to much heat for melt down. 180 tops. it works in first but seems to slip pretty good when i hammer it. the tran brake won't enguage. when i put it into neutral and push the trans brake to go into reverse it slips extremely bad and won't even move the car. have plenty of fluid. all other gears work fine. it won't reverse even if i put in straight into reverse eother

 

There is a transmission tech page at yellowbullet.com you could probably find the answer there.