I don't know if you figured out your problem yet.. might not be the answers your looking for but here ya go..
I have a 97 F350 PSD i'm going to school in Chicago but live in northern michigan.. recently i went to drive back to michigan and i ran into the same problem.. my O/D light was flashing.. i got into town and went to my local tranny guy, hooked it up to the scanner and the code was for torque converter slippage.. pulled the pan and pieces of my torque converter fell out.. Turns out my year truck was when they started switching to the 4R100.. that made me happy.. but i had the Tugger kit put in by TransGo.. and a triple disc TC. It really shifts good and firm and with the kit it doubles the holding power in Low and Reverse.. so its great for towing.. So as far as the valve bodies the Tugger kit is a nice one.. not that expensive either. If you've got a stout driveline you'll be able to cruise at 60mph and with the tugger kit throw it into 1st and it will hold...
if you have more questions i can get more info..