I have a '01 grand prix gt 3.8l auto. the trans was rebuilt at 95k, car purchased at 98k. It now has 123k and for the last 10k the trans has been acting funny. Upon takeoff or when I slow down and turn then start to accelerate the car "shakes or jumps". If I floor it it normally stops. It is like when I slow and then try to accelerate the trans has not downshifted. The car never stalls. The problem started intermittantly, but is happening more frequently. I did some research and the TCC seems to be a possibility but most of the other cars I have found with this problem stall. Any help would be greatly appreciated. TIA

I forgot to mention that I just changed the filter and fluid and added Lucas oil trans fix. The pan was almost spotless inside and the magnet was still in place.