Last week, my wife and I purchased a 2000 Mercury Sable LS Premium for our daughter who recently graduated from university. It has the 3.0L Duratech 24V V6, and the AX4N transaxle. The car was purchased from private party, and has 36K on the clock.
Apparently, power steering pump problems are quite typical for the vehicle. The PS pump makes quite a bit of noise when the steering is on center, but more so when turning from lock to lock. From my experience, it sounds like an aeration and cavitation problem, rather than an actual PS pump failure. I know the Ford shop manual specifically goes through the purging/bleeding procedure thoroughly for this system.
I took it to a good independent shop, and they stated that there's also a screen in the external PS fluid reservoir that can become clogged which can exacerbate the problem. Moreover, the specified PS fluid is Ford-spec MERCON ATF, and I will be willing to bet the previous owner used standard PS fluid to top the system off in past years.
The shop's first step is to flush the existing fluid, clean the screen in the reservoir, and then refill with ATF, and bleed the system. And, then go from there . . .
Any thoughts on this from anyone more experienced with this on the Sable and Taurus with the non-integrated PS pump system would be greatly appreciated.
Thanks, Don