Just got back from track was running good, made 6 runs around 10.2. Let the car cool for a couple minutes and lost all forward gears. Still has reverse, and when you apply trans brake in first, it tries to back up.

727 trans was rebuild be decent shop around 25 passes. Not sure who valve body, but don't need to apply trans brake to back up in reverse.

What first thing I should check in the morning?
Dragweek coming fast.