:If it works i wouldnt fix it, these bearings may outlast the car.
I had a humming noise from the rear of my 2002 V6, Camry, that i could not pinpoint. I even swapped tires, no change in the noise. I changed BOTH rear hubs (its an easy job) but they cost $125 each. The
noise did not go away!

I thought about removing the new ones and cleaning them up for return, and reinstalling the old hubs - probably should have - but the car has 133,000 miles so i left them on. (Pretty costly preventive maintenance actually i thought.)
Finally i replaced 3 tires the noise went away!!!!
I figure that the noise was really tire noise. I often buy cheap tires and a lot of times i wind up with radial pull on the front tires, which drives me crazy. So i wind up swapping the tires around in front until i get a pair that wont pull.
I figure the old urban myth about NOT changing direction of rotation on used tires is no myth at all - i swapped some of the tires from one side to the other in an attempt to make it not pull, thus reversing direction of rotation. And this caused something bad to happen with the steel cords in the tires and made them make noise.