Mine did the same thing, however a bolt had broken inside the tranny. You said it felt like the shifter was disconnected from the tranny. Do you mean that you can't feel any of the gate's? That's what mine was like, no gate's no nothing just stuck in third. Hope this isn't your case though, but if it's still under warranty, Ford should pay for it.
Could also be the shift cable broke. Just my two cents.
Mike
