[vad]

Because FoMoCo has nothing to do with your problem. And I'm on your side, don't get me wrong.
FoMoCo doesn't own the dealership, therefore it's not legally liable for its wrong doings. The same goes for the rest of the dealerships. They are not liable too.
The dealerships are frunchises and are operated independantely from Ford and each other. Unless the dealership you go to is fully owned by FoMoCo(which is rare).
The only solution in my uneducated opinion would be contacting the dealership owner and politely (important) ask to fix their mistake (tranny flushing etc). If unsuccessful all you can do is sue the dealership for damages done to your tranny in the small claims court.
Do you have any, beside low mileage and vibration? It's kinda hard to prove in the court.