Took mine to the stealership and had the transmission serviced, system flushed, all fluid changed to Mercon V, she seems very smooth now, I think I was having a bit of torque converter shudder which I do not feel at all any more. 131,000 miles and no idea of previous maintenance performed and I tow, they said the trans. had definitely been serviced in the past and it and entire vehicle is in very good condition for age/mileage.
What was your shudder like? i.e. what speed, how long, more of a vibration or wiggle? I changed my fluid with filter and such too but still have a shudder that I hate!