So I recently just bought an FJ (yay!) it’s been amazing so far and when I bought the truck I knew going into to it the power steering fluid was pretty low, but the time has finally come upon me. I’ve done my research and found that Dexron II and III are manufacturer recommended but have heard Mobil 1 synthetic ATF is just as good if not better as long as you drain it annually. I have the “pleasure” of living in Minnesota so we get temps of 100F to -40F as extremes and the truck will be parked outside yearlong and the truck is black. I guess my concern is if any one doesn’t perform well under pretty moderate heat and much more worryingly extreme cold and if there is any long term effects from either or if there is some other “concoction“ to put in that I’ve missed. I have a 07’ TRD special edition. Thank you for your time.