Can Bad Ujoints cause damage to differential bearings?

Is there a relationship?? Will a worn ujoint cause the rear diff bearings to go bad??
How do I inspect ujoints?/
I have visually checked them and they are ok. I tried to move the shaft and it wont budge...
What do you think?


EDIT: let me also tell you this: Ive had to replace the diff bearings twice now and the second time the dealer replaced the whole rear end. So, once again...do you think a bad ujoint cause the above?Thanks JS

A bad U-joint can cause some problems with diff bearings, but it would take a while for this to happen, and the vibes would have to be pretty bad.

All driveshafts produce harmonics to some extent, and differential bearings are sized large enough to withstand this.

Your rear axle went out because the build quality of 8.25" axles sucks. They are hard to get the noise out of, and I have a theory that is due to sloppy machining tolerances that put the pinion out of square with the ring gear.

We've had to replace two rear axles in our work Cherokees because of pinion bearings being wrecked.

A Dana axle of any flavor but 35 will solve your problems.

CRASH

Are you serious...? Two axles with stock suspension that had to be replaced? Damn. What exactly was the problem? You said pinion bearings but how about anything inside the diff?

Im not sure if this matters but when the dealer replaced the axle, he replaced it w/ a D35 not a D35c...
Either way I still have this weird humming noise at almost exactly 65mph and fades at 67mph. No vibes just loud hum, almost like a big V8 is rolling up behind me...

Although I havent had any problems with mine it has been noisy.I had some noise from the get go.I think it got worse with the gear change.

I think w/ the 4.10 things spin faster, making the chances that youll hear something greater. I read that somewhere...

What kind of noise was it anyway? Was it anything like the loud humming I get??

Yeah,as you describe earlier plus I would add "a cyclic drone"to that.

Was that stuff going on before the lift??

Yeah but not as noticeable,but with the first lift (3"),it just went downhill from there.I agree about the rpm's,I want to eventually go to an ARB so I was hoping that a new carrier and maybe some new gears(different brand) it might quiet down.

Anyone else have any more input?

CRASH said:

A bad U-joint can cause some problems with diff bearings, but it would take a while for this to happen, and the vibes would have to be pretty bad.

All driveshafts produce harmonics to some extent, and differential bearings are sized large enough to withstand this.

Your rear axle went out because the build quality of 8.25" axles sucks. They are hard to get the noise out of, and I have a theory that is due to sloppy machining tolerances that put the pinion out of square with the ring gear.

We've had to replace two rear axles in our work Cherokees because of pinion bearings being wrecked.

A Dana axle of any flavor but 35 will solve your problems.

CRASH

Click to expand...

I just replaced my U-joints and got rid of one noise now I have noticed another. It only happens when I am going on a highway downhill, if I lift on and off the gas pedal over and over while in gear I hear a soft slamming noise comming from the back, is this my pinion bearings going out? 1999 XJ 5.5" w/ SYE, 132,000 miles. Any ideas? thanks

I figured it out, the chain in the T-case needs to be replaced.