I just threw in my superduty diesel as an exampl of all different fluids and needing to carry them all (diesel oil, mercon trans fluid, royal purple ps fluid, diesel antifreeze, dot5 brake fluid, methanol, fuel additive)

I was originally talkin about my 90 F-150. I'll never put mercon v in anything I own unless it came that way from factory. The 4r100 had mercon3 or regular mercon, Not mercon5. You can use either fluid in it, because it's backwards compatible. It's just too expensive for my liking.
I'll replace my ATF fluids all with the same brand ATF. It will make for topping off and replacing it very easy.