Dex VI should not ever touch the inside of your power steering system unless you drive a small amount of crossovers gm made in like 2011-2015 where they specifically designed a new steering gear to replace the originals and used dex vi instead of ps fluid in those. PS operates under higher pressures than transmissions, and the ingredients in the synthetic dex vi dont like seals in ps systems so much. a big part of it has to do with air in the fluid, and thus heat, thus cavitation, and thus worn intenrals and burnt fluid, and thus less lubrication, and thus shortened service life