I think I have a Tranny Problem

Here is my problem it just started within the last week. I was stoped and then hit the accelerator pretty good and my car hesitated and felt like the tranny or some kind of pully slipped. then as I was driving with about 4 people in my car I was at 30 mph and I felt it shift real hard. It only does that once in a great while only when Im at real low RPMs. all the gears shift real smooth. it only the take off and low Rpms. I checked my fluid and it was High so I took some out now its perfect. I put my car into 1st gear and it made like a scratching noise like metal on metal rubbing. I shifted to second and third and it went away. I took it around the block first starting in first to hear what is sounds like when I get the RPMs up there and when I did that the scratching noise got louder. and when I shifted into 2nd it went away. Please someone help. I really hope my Tranny is not going. could it be some kind of sensor? Gear? Plates? Thanks for the Help.
Its a 1997 Grand Prix GT with 98,000 Miles. I just had new filter and tranny fluid put in like 1 month ago.
Kyle

i have actually heard of that happening before. i dont know much about trannys but i would take it back to the place that did it and bitch.
show them the reciept if u have it if not good luck!

Dont count on your tranni being gone yet...I was told by a trasmissions place that I needed a new tranni, my was slamming into gear and sometimes seemed to bog out when accelerating, turned out to be a MAF sensor and O2 sensor , I understand that any kind of engine problem sends incorrect signals to the tranni and acts like a transmission problem...have your computer scanned and see if it finds any engine problems before you even bring it to a transmission shop... I was told 2400 for a new tranni I didnt even need....good luck