Annoying whirling noise at mid to high speeds.

I just recently bought my car an 02 Q45 (F50) with 60K miles.  Sport edition.  I noticed while on a long freeway drive an annoying whirling noise.  It somewhat has a pulse to it depending on my speed.   Becomes very noticeable at around 45+mph.   I was thinking either the tires are doing it which are in still good condition with Yokohama ES100 tires all around or the wheel bearings are shot.   Does anyone else notice it on their Q?   While driving around 65mph do you get an annoying whirling sound?   I remember someone in here saying they had to replace their wheel bearings.  How did you know?    Could it be my transmission?

try changing ur differential oil and transmission oil. if it doesn't fix the problem, it's a good thing to do anyways.

[QUOTE=Caoboy;42128]try changing ur differential oil and transmission oil. if it doesn't fix the problem, it's a good thing to do anyways.[/QUOTE]

yeah..probably a good thing to do.   What fluid do you guys recommend?   Just regular ATF or should I get what Nissan sells.  Synthetic?    and what should I use in the rear diff?

I would of said the wheel bearings. Parents own a tranny shop. Too bad you're not in Norcal. But check your tranny fluid. Make sure its top off and if its red and doesnt smell burnt. You're pretty good. Tranny fluid should be changed at least every 24,000 miles.

Its the tires. The ES100's when worn down unevenly are notorious for road noise. Their new tire, the S.drive (dna tire in Japan) has grooves cut in it that help reduce the hum. 
 
I had ES100's before and I'm familar with the sound.

I always thought it was the tires and wheels that made the noise too. The tires effects mainly.

[QUOTE=mdenoga;42155]I would of said the wheel bearings. Parents own a tranny shop. Too bad you're not in Norcal. But check your tranny fluid. Make sure its top off and if its red and doesnt smell burnt. You're pretty good. Tranny fluid should be changed at least every 24,000 miles.[/QUOTE]
i always change it out when i change my oil. not a flush, but just drain the pan and refill it. i'm too lazy to flush it out, and dont want to pay the 170 people charge to flush it.  works, probably not as well, but keeps the fluid looking that clear/red color.