tranny problems

Well i have had my 95 gt for a month and it has had some minor (i hope) tranny problems (that i didnt notice till after i handed them the money ). its a manual and has the t5 i would assume and it also has a pro 5.0 shifter that the previous owner installed and 90k on the car. I did a search and didnt find a whole lot of info that i was looking for. going up through the gears normally it is fine but when i downshift into 2nd i have to give it a hard jerk (always seems to go into gear on the 2nd quick jerk), and it also sometimes grinds when i downshift to 1st. Now that is all in normal driving. I also noticed when i hot rod it and i go to shift into 2nd it grinds badly and then goes into gear on the 2nd attempt (not powershifting even). it grinds in reverse unless i put it in another gear first but this is normal cuz it has no synchro right? The clutch is supposed to have an adjustment. you adjust it by putting your foot under the clutch and lifting up and then slowly depressing it to the floor right? this seems to do nothing to my car. the pedal doesnt even seem to lift up.maybe i need a new cable? anyway to tell? i am going to check the tranny fluid tomorrow just to make sure that it is ok. how hard is it really to rebuild one. i have access to normal hand tools, but that is about it. any input is welcome.