Ok, I posted a question regarding a noise I have in my newly-acquired '99 Sport. I originally posted it as a tire question, but I'm not so sure it's the tires, so my question might get more responses with this thread:

So I bought a used '99 XJ Sport. Auto, 231, D30 RR, 8.25 rear. Anyhoo, I get a dull roar that starts at about 25-30 mph and gets louder. I have no idea what is causing it. I'm told it's not the tires, as I've searched and no one who has them (Hercules Terra Trac A/T) says they are loud.

It's not what I'd classify as a howl. It's definitely not grinding. Not metallic sounding. And it does it on or off the throttle. The pitch does not change with asphalt, concrete, etc.

I changed the fluid in both diffs; found nothing crazy. I've shaken both pinion yokes up and down, side to side and found no play. Only play is rotational backlash.

So what could it be?

Emrah

 

Dragging caliper? Carrier bearing? Lots of stuff...

 

Yea it could be a bearing in one of the diffs. I've seen bearing stay tight but still make noise. I've taken them apart and found the roller's pitted from foreign material floating around in the oil before.