This is the first I have heard of using type F. I have used dex/merc. I thought the atf 4 superseded the dex/merc for the mopar crowd. Just asking cause I'm hopefully a few months away from firing her off for the first time.
ATF +4 did supersede the dex III and in newer mopars you need to use it but in our 904/727 and 500/518's you can still use dex III or ATF +4 the only difference is one has friction modifiers and suppose to be synthetic
Type F is what B&M rebrand as there "slick shift" fluid, I think its called... it has a higher friction coefficient than dexron.... DONT use it in a lockup or any modern Chrysler transmission, as it will shudder....