oh jeeezzz... umm how long will it take for them to repair it if its the tranny? what else could it be?

 

Well, the park issue, if not the linkage out of adjustment, would be the locking pin has broken off. This means that there is nothing hold the truck still. All park is, is a pin that sticks into a notch in a disk to lock it in place. I don't know how that it would have broken off while driving unless it got shifted into park while rolling.
The grinding could be the park pin getting tossed around in the tranny. So far, mine has worked flawlessly for 19K miles. Hopefully it will continue to do so. But, at least I have the lifetime powertrain warranty, if not