01 XJ Diff Noise

I just bought an 01 XJ a few weeks ago with 36k miles on it. Both diffs are making a little noise which worries me.

The front makes a consistant "scraping" noise similar to a bad wheel bearing. The noise isn't really that loud. Is this noise normal? Pinion bearing perhaps?

The rear howls at 50-55 MPH under certain throttle settings. The dealer where I bought it thinks it's the carrier bearings, but they didn't even take the cover off. I am not confident in their diagnosis. They have agreed to replace the carrier and side bearings. Is there anything I should know to make sure they do it right and actually fix the problem? What else could it be if they are wrong?

EDIT: I should mention that there seems to be slack in the rear end. It clunks when I brake and then hammer the gas, or when changing from D to R or R to D.

Thanks!!!

Sparkman

have you checked the u joints, fluid level? maybe even trying to change fluid?

Yep, I have checked the levels, both fine.

I should focus my questions a bit.

1. Is some noise from the front diff normal? I haven't owned a live axle 4wd before (just 4wd cars up till this), so I don't have a frame of reference. I will be over at my friends place tomorrow, he has a '94, I will go for a spin in that to get a listen.

2. Can they really diagnose the carrier bearings without removing the cover?

3. Is what they call the side bearing what I would normally call a wheel bearing? Should I insist on new seals?

Thanks!!

Sparkman

I had a carrier bearing go bad in my 87, the noise in the car from the back seat was so loud you could hardly carry on a coversation. The people that owned the car previeously pulled a boat, and the mechanic figured they got water in the diff. Noise in the front may be an axle u-joint, I had one of those go bad and it was a grinding typ noise.