Years ago I helped someone pulling a tranny from an Olds Toronado, if I'm remembering correctly the torque converter would get stuck on those contraptions. I'm remembering the tranny was off and the bellhousing and transmission were separated.
He had tried several ways to get it out and it wouldn't budge.
I finally had him hold it up off the floor and I used an air hammer on a block of wood on the side of the bellhousing and hit it, it fell right out.
Don't know if you could set something up or not but a thought.
Edit, correction, typo.