Well on my 01 Sport, I have a light hum coming from the front end of my jeep in 2wd. Now I'm wondering a person told me that XJ hubs usually go bad around 160,xxx miles and they get flat spots in them. Now the noise doesn't change when I turn the wheel and stays pretty constant. So any way to check the hubs to make sure they are junk?

 

Where is the noise coming from? Left? Right? Both? A constant hum could be several things from tire noise to the front driveshaft to a front differential worn or low on fluid. I'm a bit iffy on this being a hub as it's typical for hub bearing noise to increase while turning in one direction and lessen while turning the opposite, but a constant noise isn't unheard of...just less likely.

To check the hubs: Raise the front, grab front tire at 12 and 6 o'clock and try to shake the assembly . You shouldn't have any movement in the hub.
Turn the wheel by hand listening for noises and feeling for anything rough or grinding.
You'll also likely notice one hub hotter than the other after a drive if one is bad.

 

The noise is really hard to pin point. I siphoned and refilled the front diff and while it was full the fluid was grey from condensation. I checked the grayish fluid with a magnet and found no flakes of anykind. I just had the front drive shaft fully 100% rebuilt and balanced less then 40 miles ago. I just really wanna figure out this issue as I'm really getting sick of tracing problems and spending money on it (my Superbee is feeling left out).