[sammyg2]

That's an easy one. Take a look at the damage on the ring gear. No where near where the load is supposed to be.
Something got distorted or out of whack to the point were the load was no longer transferred to the center of the gear where it belonged, instead it was transferred to the edges of the teeth where it shouldn't be.

The failure did not start with the gears, they are the result and not the cause.
My bet is either a bearing let go or some other mechanical failure which resulted in a significant misalignment of the gear mesh.