I haveused the two together in a P/S system useing Dex III with no problems. While I am not an expert on either chemistry I have had this combo in for a long time! Typical p/s presures are rather high and the heat can also get high. If I was going to have a problem I would imagine it would have showed it's ugly face by now. When you consider the extremely low amountof LC involved in the transmission and p/s sytems I think it would be difficult to get any conflict. I too figured they would compliment one another both being anti-oxidents(sp).
