Jeff's 727 rebuild thread
Why not, if you decide to pull things apart, just drop the valve body, disassemble it, thoroughly go over it, inspect everything, have a look at that plate, compare it to the Transgo shift kit instuctions, I think theres a picture of a separator plate on one of the pages if I recall correctly? And if a new valve body is what you settle on, I wouldn't rule out trying to source an nos or good unmolested one, or maybe someone here can hook you up, and just transferring the Transgo pieces to the new one. Just another cost efficient option to consider if it isn't something else entirely.