tub stuck

I am attempting to remove the tub on my washer and. It seems to be stuck. I removed the agitator nut and the 6screws underneath it and I still get no movement. I also tried to oil it with wd40 and still no movement. The last thing I have tried is filling up the tub with water to get it to float, but it still will not come out. Am I missing something or should I call a professional?