New Noise..any ideas???

[Williams1279]

I've got a 2000 ML430 with 110,000. Its recently started making a sort of whining noise(not ebox fan or steering pump). At low speeds you can hear it over the engine noise and at higher speeds the normal engine and road noise are louder. It only occurs while driving, there is no noise while in park or at a stop, only normal engine noise. To me it sounds like it might be coming from somwhere on the passenger side front of the vehicle. Its not tire or suspension noise either. I'm just guessing maybe front differential or transmission, but I'm not an expert. I just changed the transfer case oil(old stuff was pretty brown) and engine oil/filter. However i've never had a transmission issue and it still shifts and drives like it should. The noise also does not fluctuate with the shifting of gears either manually or automatic, its just a steady whining noise. It seems like it get less prounounced as the car heats up as well. Does this sound familiar to anyone....i'm dreading bringing it to the dealer, they can be so out of control. Any help or insite would be greatly appreciated, other than a sloo of problems, i still love my ML.