2001 Mercury Sable

Transmission problem
2001 Mercury Sable 6 cyl Front Wheel Drive Automatic 101000 miles

My 2001 Mercury sable is not shifting down the way it should. If I drive like 30 mph and stop and try to go it will jump because it hasn't shifted all the way down. The fluid was low, I checked with the motor running and added some. Also, when I had the dip stick out and shut the car off, the fluid started bubbling up and out of where it goes in and it smelled hot. Could this be caused by a bad filter or does it sound like a problem I need to have a professional fix?
October 25, 2010.

Is the fluid still clean? Does it have a burnt smell? Have any warning lights come on?

Yes fluid is clean, did smell hot. No lights

Oct 26, 2010.
It sounds like the trans control module (TCM) is bad. I would recommend having it checked.