Exploding Torqueflites

Good information here. Not to Hyjack the tread but, I have an Art Carr reverse Manual valve body, it has been in three transmissions so far and in every one of the trannys it locks up between 1st and 2nd gear. I have had several people look at it, but so far no one has been able to fix it. the dang thing will darn near throw you thru the windshield. Any ideas would be greatly appreciated.