I am beginning to think it's some sort of "support" related thing that has failed.
I was told to make sure the differential supports were good, as that could be a problem. I do know that 200 lb/ft or torque is quite a bit of turning force, and it only makes sense that something related can wear over time, especially when pushed hard.
Any other ideas?
(BTW, car has 101,000 miles, original trans)