I checked out the rear wheel bearings and CV boot/shaft/ bearings on my audi A4 98' 1.8 (aeb) and they appear to be ok but there is still excess road noise. It sounds like a bearing problem of some sort but the wheel doesn't pull to either side so I don't think its a front wheel bearing....could it be a problem with one of the differentials? the sound oscillates somewhat at speed but doesn't change pitch

 

a bad wheel bearing unless its binding won't cause it to pull when driving.

you wanna check your wheel bearings... jack up the wheel you suspect being bad and spin the wheel freely. put your hand on the knuckle where the upper control arms mount in and feel for a vibration...

 

is there anything else that could possibly be the reason?