Lose the Type-F in your T-Type/GN's
When I bought my GN, it's 2004R had less than 500 miles on a rebuild and was filled with F. The T.V. cable was tighter than a nun's fun-box too, but that's another story.
When the TCC solenoid quit and I replaced it with one for a 700R4, I took the board tranny gurus' advice and went back to Dextron III.
Surprise! The shifts feel fine and probably runs cooler too.
I use Type-F in my early TH-350/SBC and it seems to have a crisper shift. Lenco planetary transmissions are designed for Trick Shift or plain old Type-F too.
So although F is fine in 70's era units, do yourself a favor and stick with Dex or Bruce's (WE4) snake oil hydraulic fluid.
HTH Jim