Diesel for agricultural use is non-taxed dyed fuel.
Ruby Red is what we call it on the farm. Construction companies also use this fuel for equipment, anything that
does not drive on federally funded roads can use this fuel.
It's your truck, do what you want, but when a

wants to "dip" your tank and you have dyed fuel, expect to pay.
I've been dipped a couple times, once when I was following a combine with a fuel wagon of dyed fuel. The

asked to pop the hood and look at the fuel filter, I was good to go and happily complied. I have put 5 gallons of died fuel in my tank to make it home from the farm once, the dye stays for a LONG time!