I am going to drain the power steering fluid in my 2001 Dodge Grand Caravan. I replaced the rack a few years back and put Mopar Power steering fluid back in it as this is what the owners manual said. I see a lot of people put ATF+4 in their steering system instead. Did I screw up?. I need to replace the power steering reservoir again ( it whines on startup) and thought about draining the whole system. What does anybody think?