first of all, service of the car is the owners responsibility. you need to have the fluid change at the intervals suggested by the company.if you dont, then the process of failure has started.
i have not heard of this being a real issue with these models.
anyway, it sounds like it lost the torque converter. 5000 is way too much for this repair. if i were you, call a trans shop for a bid and you will see that it runs around 1500-1800 depending on hard parts. dealers are very high and in this economy, you need to do your homework for the best price.
no, ford will not be held accountable with the age and the mileage.
Roy