Humming Noise...
 

Greetings good people, as an introduction, 2007 E70 X5 4.81 with 100K, my problem is this: All the fluids has been replaced in the truck, front and rear differentials, transmission oil change, so all the perks...
The truck is running perfect, but I have this noise from 20 to 60 mph, but you can't hear it if you have your foot on the gas, just when you let it go is when you hear it... is like "whoosh"...and believe me, is annoying...
I have to replace the rear tires, but i'm more inclined to the bearings... any help will be more than appreciated...

Bearing when defective do hummmm, there should be a scientific way to check that.