Last night I noticed for the 2nd time this. I had just gone down a pretty long steep hill and was starting up the othe side, speed was about 60, as I got on the throttle I felt a shudder or small slip as the trans shifted from OD to drive to pull the hill, then everything was fine, it upshifted as it should and no other issues. Anybody else seen anything similar as the trans downshift under load?
thanks,

 

I just got my Town Car out of the garage a few minutes ago for this problem. The shudder was the torque converter locking and unlocking and is caused by the deterioration of the transmission fluid. It is a common problem. The changed the fluid (10 quarts) and filter. It corrected the problem. I found out it is a common problem with Ford transmissions and they recommend fluid changes every 30,000 miles. It is a synthetic fluid. The fluid cost more than the filter and labor.

 

I had a similar problem years ago in a Mercury Cougar I owned. It would shudder under light acceleration at about 45 to 50 mph. Turns out it was the Torque converter. Ford replaced it under warranty.......Good luck.

 

I got a similar issue except mine is on upshift after climbing a hill with OD off and then switching it on after cresting the hill. Sometimes it's smooth other times it's a horrible shudder. I just hit 1500 miles, how could the fluid be shot already??? I'm guessing the fluid change masks the torque converter issue until it gives out totally? Maybe I'll set up an appointment and get reflashed while I'm at it.

 

An ignition coil breaking down under load can feel a lot like a torque converter shudder as well.