Ok I have a 82 firebird with a 305 and a TH350 trans. Its been running like crap for the past couple days. I accidently put in some type F fluid. (I didnt know there was a difference) so I changed the filter and fluid today and used Dexron 3. But its still not better.

Symptoms: Drive niceand slow and it shifts fine and hits third gear at like 25 MPH. Try and give it a little gas and the problem comes in. Its not slipping but its like its not completley hooking up. I cant get all the power I used to be able to get. It wont shift unless you let off the gas. It will just stay revved to a certain RPM.Like its about to shift. Same thing with 2nd-3rd gears.Once your cruising in third you floor it and it immediatly revs way up but you really go nowhere.
Now if you really floor it of the line, it just revs high and gets no power and you cant peel out or anything (It used to just slam the tourqe to the pavement)But when you hit the 2nd-3rd shift Theres a bad clunking and shaking for about 4 seconds. Sounds *** Awful. And after you get that reaction,If you go to park it the shift linkage will act up. Every gear but Park is Drive. Turn off the engine and shift through, and every gear is nuetral.
I dont know much about trannys so I dont know whats the matter or what to do. Any help would be apprectiated Im watching hondas take off while Im practically stuck in the mud. This sucks