other than one specific year (forget exactly when) that Mopar said to use one or the other/ but specifically said NOT to use the other fluid between the 2, it was much newer than you are talking.... but the next year, they flip flopped back the other way. otherwise I have seen them say to use one or the other, with the other as an "acceptable substitute".


I would say to use which ever you have on hand and keep it that way..... not inner mixing the 2, would be the more important factor. If you start with ATF, keep it ATF as long as you continue to own it.
same thing can be said about "power steering fluid" if you wanna swap fluids, drain and flush the old stuff out, and run 100% of one or the other. all the time.