I drained and double rinsed (flushed) the system on my Ram 5.7, and put Prestone in it. That was 4 years ago. It is now due to drain and put fresh. The same stuff is going in, Prestone. You should be able to put whatever you want in. The caveat that everyone is saying is: ... do not mix types, ever. If you are going to put something else in, it has to be the whole charge with a complete rinse first.
Same thing is going to happen here to the Dakota 4.7, Prestone, soon as I am finished with refreshing the Ram. I am just waiting a few days for the cold snap to break, warmer weather, so I can run some water. It was -36 deg Celsius here this morning. Brrrrr.

 

Which coolant for 2015 Ram 6.7 2500? Just purchased used 94k.

 

What does your owner's manual say...?