2002 Tranny problem

I have a 2002 Ford Windstar that has a rough "shuddering" for about 1/2 second when I give it a little extra gas. It is most apparent when in O/D at about 60MPH starting uphill. With the O/D turned off it is not as apparent but it does the same when in a gear and the accelerator is pushed down a little. 82000 miles, minimal towing. Any ideas?

Minimal towing? Does this mean a heavy load for a short time or a light load for a long time? or something else. Do you have the towing pacakge or an additional transmission cooler?

Light towing - 1200 lb pop up camper 1 time - 85 miles each way with O/D off. Does not have tranny cooler.

Judging by your description it almost sounds like the torque converter lock up not releasing cleanly but obviously we wouldn't conclude that just yet.

Have you changed the fluid regularily? Have you changed it recently? If so did you use Mercon V? Is the level up to the top?