I've had great luck with Redline PSF. It claims to meet the older PSF spec. from GM. I'm personally not familiar with a newer spec. if there is one. It meets the spec. for both my cars. I did an AutoRX on the power steering in my wagon and then flushed with the Redline and it fixed an occasional cold weather problem where I'd start out with no power steering. It has worked flawlessly for 2 years now.
Originally Posted By: George7941
I just replaced the original fill GM PSF with Mobil1 ATF in my 2006 Sierra. So far , so good. This, in spite of GM specifying PSF only for my truck.
I have been using M1 ATF ever since they came out with it. Early 90s I think. I have never had a PS pump far with M1 ATF in it. Also my pumps have always been quite. Same with my trannys.
