T-5 problems?

Today i was driving my stang pretty hard getting used to the new intake and around 4 grand my tranny started making a weird noise like somthing was dragging against the shifter and a sort of grinding noise also kinda hard to explain. It did it in 2nd and 3rd so i shifted it and kept driving well it did it again and it has me stumped it only does it at higher RPMS any ideas?
 
Simple things first. Crawl under the passenger side of the car and remove the sight plug on the side of the tranny (not the one on the bottom, that's the drain plug). Make sure that the tranny is full up to the sight plug. Also remember that the T-5's use Dextron/Mercon ATF, so don't go putting gear oil in there!
 
about a month ago i checked the fluid level but i will check again and i dont understand the last post blown in do you mean it? or what i dunno what to do i am too poor to buy another tranny right now and i put in ATf fluid not gear oil
Also why would it do this at high RPMS and not lower if i tore somthing up?
 
it makes it almost all the time when i run it up to 4 grand it feels like somthing is rubbing on the shifter it is hard to describe. Since i just put a new intake on my timing was set by ear, so i dont think it was pinging but i am going to put the light on it when i get some time. Also if i did chip a gear at the high rpms wouldnt it effect the low rpms also since it is damaged? i am not a professional mechanic so i dont know any help is appreaciated