Buddy

So i herd that our V6 auto tranny's are slush box's. recently i have been stepping on it and ben racing it to death. i have started to develope a slight shimmy in my tranny and strange things happen. i can tell its from my tranny. i have added SMALL SMALL amounts of transmission floudid every so often.... if i over fill it how much damage can be done? and also does the tranny lose any flouid over a duration?? especially in the hot miami sun??? because i think i added a little to much and she is lagging in shifts.

also
Is the mustang GT Auto tranny exactly the same as my V6 tranny????