My car whistles a little

[99ggp]

I own a 2006 GP GT 3800 Supercharged, 33,000 miles. I bought this car slightly used, 16k miles on it. Shortly after I bought it, I noticed a slight whistling sound only when I turn right at around 20 mph or so. Its a really low sound, if I have the radio on or the fan running I cant hear it. A week ago I notice that the power steering fluid was leaking around the module that the steering shaft goes into (not enough to drip on the garage floor but just enough that fluid was collecting on the module). I took it to the dealer and they found that the fitting on the pump return line was leaking and replaced it. Well, the slight whistling sound is still there and Im debating whether to take it back and have them look at it again. Does anyone else have a similar problem or know what is causing it . Any help is appreciated.