I just added approx. an ounce of Auto-RX to my PS fluid (which was changed recently) to see if it helps quiet the whine. I immediately noticed that the whine had quieted and the PS seemed lighter (smoother). I plan on running this 1K and then changing the fluid as per instructions. I have to decide whether to use PS fluid or Mobil 1 ATF in the system when the 1K is up. The car is an 02' Buick century with 105K.