PS pump on the wife's 02 Caravan has been growling for better than a year now. Might need a new pump but gonna try just a fluid change first. Owners manual says to use ATF+4. Can I use the synthetic blend SynPower PS fluid that I use in my truck in the van too or do I need to stick with the ATF+4 stuff? Might there by any advantage of the SynPower over the ATF+4? I think the ATF+4 is also synthetic - or partially so.