Glad to see you've found the problem. Thanks for the feedback.
Oftentimes the rings of a 'vane' style pump will break causing all kinds of havoc. Increased pressure demands is hard on stock parts.
Torque converters have a turbine and a stator that 'hang' on the input shafts of an auto trans. So it's hard to determine the health of a TC while separated and lying on the bench. The stator has a one way roller bearing that can sometimes fail. But again, hard to see into the TC snout and check. Usually if the stator one-way fails you will loose all drive forward and reverse. Rising trans temperatures will aggravate this accompanied by very strange grinding noises. It's good to see that you replaced the TC anyway.