2000 Expediton Transmission Problem

I have a 2000 Expedition, its transmission recently "fell apart".....the mechanic said it was completely broken and pieces had fallen off. A friend who also has a 2000 model said the same thing happened to her, my brother has a 2000 navigator and the same happened to him (aren't they Lincon/Ford as well?)
Anyway would like to hear from anybody who has had a similiar experience....I've never had a 5yrs old car go through such a huge problem.