Im with you on all that John. The one trans that comes to mind is that old Power glide.....if it was full of varnish, a screen & fresh fluid would fix the problem(assuming no metal or clutch junk in the bottom). That is why I suggested dropping the pan(whats inside the pan will pretty much tell the story)
Hope for the best, but be prepaired for the worst. Dad always showed his 3 boys to take the cheap easy route 1st.....if it didnt work, then go fight the problem. I too hope the easy route works, but I am skeptical also. Best of luck,crazyAL