Hmmm....could the same thing be done by taking the bolts out of the flexplate and trying to rotate it on the input shaft while still installed, or would that not work the same way?
" This might work, although I've never heard of it being done this way. Remember doing it this way, you're also turning the pump and the forward drum." transman
If the converter went bad (worn impeller/stator vanes) wouldn't it essentially "stall" to a higher RPM? Or is it possible there is seizing inside that basically turns it into a lockup converter?