Seems odd that Ford would spec 'GM' fluid, but it is what it is.
I don't have an automatic, so I can't really say.
I hope Dex/Merc is a good answer for my TC, because I don't want to go through that again any time soon.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.