I do not know about a difference in part for the O-ring, sorry. But I do know the changed out and topped off my power steering fluid, as it was listed on the invoice.The whine has disappeared, but now I'm a little nervous about future problems. I have started experiencing for the first time this 3rd gear issue everyone seems to complain about with the 6mt transmission. I thought it was in 3rd gear and I released the clutch and heard a grinding noise and then it popped out of gear?? This has happened to me twice. I have also noticed it's occassional very "notchy" for lack of a better word; almost difficult to engage at times. Oh man, I really didn't think I would have to deal with issues like this buying a Honda. No buyers remorse yet, but in the four years I owned my Mazda 3 (a first year model no less) I never had a single problem with it except for excessive rear brake dust. Hardly a serious problem.
