i know u dont want to hear this, but it might be your torque converter. this is exactly what mine did one or two days before i took it in to get it looked at. now i know NOT to ever drive when this happens. when i took it into the tranny shop they pulled the pan and metal shavings came out. 900 dollars later it was good as new, except it was still the crappy AOD. If my dad had let me, i probably would have found a rebuilt c6 and put it in. Hopefully this isn't your problem though, but it sounds awfully similar to mine.