PS fluid options for my Buick

[pbm]

My 2002 Century with 117K had a squeeky, groany PS system about a year ago. I D&R'd it with a TB a few times with only slight improvement. I then added an ounce or two of Auto-RX and ran it about 1000 miles and then did several TB D&Rs. The system quieted down a lot with the ARX in the system and became like new after the D&R's.
Fast forward to today and the system is begining to groan a bit again despite 3 D&R's recently.
I admit that the OE fluid wasn't D&R'd until approx. 80K so it probably could use another ARX treatment.

My question is what can I use in the system as an improvement over regular Walmart brand PSF?

Has anybody used synthetic ATF or better yet ATF+4 (since I have some to get rid of) ?

I'd appreciate any feedback on what guys have used successfully in a GM PS system. Thanks in advance.

 

[sciphi]

I've used ATF in my Buick's PS system. It works well.

 

[HTSS_TR]

My '00 E430 power steering system started making noise 2-3 years ago, last year I tried several different fluids, PSF's and ATF's, none stops the squeal when the sterring was turn more than 15-20 degrees. Then I tried Valvoline MaxLife Power Steering Fluid with TB method, after 3-4 changes until the quart bottle is all used up the steering was/is as quiet as it was new. It is still quiet today. Valvoline MaxLife Power Steering Fluid can be found at Kragen at about $4.xx/qt. I will change PSF again next year with Maxlife again, TB method is easy and $4.xx every 2 years is money well spent to keep the power steering system in top shape.

 

[pbm]

Thanks HTSS_TR, I may try Valvoline MaxLife Power Steering Fluid unless I'm told that ATF+4 would work great.

 

[FusilliJerry82]

Look into installing a Magnefine too.