That right there is the culprit. No one ever thinks about just how fast ONE SIDE spins during a burnout. They are not designed for that type speed. That's what causes them to over heat, cook the gear oil and start galling the small pinion gears to the cross shaft. I agree 100% with Garrett. No way would I use anything out of that housing. I'd start all over fresh with everything, right down to the bearings and races.