I have a 04 fx4 with the 5.4.

My problem is when I'm cruzing at 1500 rpm my truck stutters or jerks. The rpm's dont change and its worse if the trans is under stress like up hill. It's not throwing a code or turning any waring light on.

I thought it was because it was thrown into park when i was going around 40 down the road but ive replaced the transmission since then because second started slipping. I have no idea what it is and was wondering if anyone else has had this problem.

 

This is the 3rd post I read today with transmission shakes. Are you in overdrive? Did you try taking it out of overdrive when it happens? Maybe run around without overdrive and see if you get the same issue. How long since you replaced the transmission if it is still under warrenty take it back and have a shop look at it.