Tip Don't expect a 25K job for 10K. Unfortunately you got what you paid for.
That be said... Be civil with the shop and see what they will do. Taking them to court could go either way. They have worked on it and tried to stand behind the work they did so far it seems. This last hiccup will be hard to prove anything. I don't see the truck going that long and spinning bearings just like that. Proving that they did something that caused the bearing spin will be hard after 20,000 miles have been driven.
Did you get it serviced since the overhaul and the 20,000 miles?