I can feel it in the steering wheel (very slight vibe) and hear a rubbing sound right at the steering wheel when I make slow speed turns, while the wheel turns. For example turning into my driveway. It's not a squeak. I don't have active steering. Is this a belt issue? Something need grease? I guess I gotta check my PS fluid too.. but I can't find a reference in the manual.

'08 3.0si with 28k miles

EDIT> updated on 6/22/12 below

EDIT> 4/30/2013: this rub sound/feeling while turning at low speeds has come back and is more frequent again. Once again, it does not have active steering. Power steering reservoir (while cold) shows halfway up to the max line so it seems fine. Anyone else figure it out?

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'08 X5 3.0si - Alpine White / Saddle Brown interior
Specs: Sport Pkg, Premium Pkg, Tech Pkg, Comfort Access, Aero Kit, Style 433 staggered 20s on Conti DWS
Mods: Carbon 35 tint, LED angel eyes, GP Thunder 7500k fogs, H&R 20mm/25mm spacers, clear reflectors, gunsmoke-tinted taillights
Coded: Digital speedo, windows/sunroof/tailgate close via keyfob

X5 pics at Flickr