I heard this pop and then....

so I wedged the drive gear in the differential and took a pipe wrench to the pinion flange and could not get the pinion to move. I do not think it is broken. With the ring gear locked up, the pinion locked up too.
So back to the clutch pack in the differential, what happens when they go bad?
How do you check the clutches without taking it all apart.

Certainly sounds carrier related then. Unless the pinion gear is broken and wedged together tighter than you can turn it.