Flushing the tranny is the ONLY way to replace ALL the fluid. When dropping the pan, you only replace about 45% of the fluiid, and there isn't a drain plug on the TC.
To the OP. I'm planning on doing the flush on mine, using BG full synthetic. It will cost me about $325 American. BG is compatable with Ford fluid, and some say the truck will shift better with BG than the Motorcraft
