There are no converter anti-drain back provisions in the Torqueflite, drain back is perfectly normal...as long as there is any clearance in the pump bushing, fluid will drain from the converter when sitting (or when idling for prolonged periods in Park). Of course, the more clearance, the quicker it will drain.
Much ado about this, but the cure is either starting in Neutral or installing the redesigned manual valve.
Me thanks you have not had one of those valves stick open and lock the converter up by flooding it, have you
I have, one of the employees at Rossi Trans and Converter CO. told me about it, it is on the top of the valve body towards the front of the valve body, it is a check ball. The car that it was race in had a tranny failure the year before and the owners had not flushed the lines and cooler out
I thought I had broken the Art Carr 8 inch race converter testing it before the 1974 Winternationals and ended up swapping it out twice, once to a stock 11 inch Street Hemi converter and the second time to a B7M O69J and both of them acted exactly the same
I called Rossi and one of his employee who raced a Street Hemi 1970 Challenger in SS/DA told me about the fix
I did it, it worked