Guys used to keep a bottle of trans fluid in the truck so if they got caught they could say they added it for lubricity and that's what turned it red. lol
Should be. Most use solvent red 164 for dyeing. It's pretty strong.
The little bit of mmo, atf, or whatever probably won't be enough to change the color.
Not all of it is dyed anymore either. Only home heating oil is required to be dyed.
Some still charge the normal price, and let you hash it out on taxes to show off road use.