98 4.0 with I believe a Chrysler 8.25 rear

I am getting what to me sounds like a bearing noise. It can almost be confused with excessive tire hum but after listening for a while it definitely seems metallic in nature. It can really only be noticed when driving 25 mph and over.

It sounds like it is coming from the rear of the vehicle but can't determine a side. My first thought to that was the rear differential hence my other thread about inspecting and changing fluid. My second thought was a wheel bearing.

One thing I should mention, I just noticed that when I backed up and cut the wheel to the right you can really hear a metal to metal noise but it seems to be coming from the left front wheel, which now has me totally confused as the noise seemed to be coming from the rear. No noise when I cut the wheel to the left. Any thoughts? And how can I determine if it's a wheel bearing or not?

 

If it sounds like a metallic scraping noise, check the dust shields on the front end. They have a habit of getting banged up from time to time and dragging against the rotor. Bend it out to fix.

 

Thanks. I am familiar with that sound and that is not it. It's not a scraping noise but a wearing noise if that makes sense. ??

 

Anyone else have any ideas? Tomorrow is really the only day I can work on this.

 

You say that it is making noise when you cut the wheel, mine used to make a noise when making u-turns among other things and it wound up being a u-joint on one of the front axles.

 

Thanks for the input. It only made that noise when in reverse turning the wheel to the right. And that noise came from the right front wheel. Normal straight driving it doesn't make a noise when turning and seems to be coming from the rear of the vehicle but can't determine a side.

 

And I know you can trying to determine a bad wheel bearing by lifting the tire and shaking it. Any way to tell if the axle u-joint is bad?

 

Ya it could be a ujoint. Have you pulled your brakes apart and looked at them? I have seen people come in and ask us to find a metal rubbing noise and it ends up being the ceramic on the pad or shoe literally shattered and a piece got stuck dragging on the rotor or drum. Try pulling your front brakes off the rotor, drums off the back, and check for signs of excessive wear. Also, most likely not the case, but it could be the rim actually rubbing not the tire. In that case you may see rub marks on the ends of the sway bar link or something of that sort. Not much but I hope I could help!

 

I did not even think of that. Big help, thank you. I'll be pulling everything apart tomorrow and I'll post what I find. Found a good video for checking axle u joints too.

 

No problem. Also when you take the rear drums off, pull out the little adjustment dial, the little bar with a gear looking thing in the middle that spans the bottom of the shoes, and shoot it with wd40. Make sure it spins freely. I don't know if that has anything to do with your problem but I believe on xj's the rear brakes only adjust while reversing. So when you said the noise only happens in the front when you are backing up it made me think of the adjustment for the rear since that's really the only part of the brake system that changes in reverse. Kinda shooting blind on that suggestion but hey who knows and since you'll already be in there might as well try it!

 

Well I inspected the front. Front drive shaft u-joints seem good, no play. Left front axle u-joint seemed good but the right front axle u-joint had a little play in it. I could move it and make a knocking sound with it. I guess I will start there, replace that u-joint and go from there. Doesn't explain the noise in the left front when turning the wheel right in reverse.

Haven't gotten to the back yet I only have 2 jack stands.

 

I do not have a pneumatic impact wrench for that 36mm axle bolt. Can those be removed by hand?

 

Yep, but I would suggest finding a 3/4" drive breaker bar, 3"extension and either a 36mm or 1 7/16" socket to do so. When they stick they kill 1/2" dr gear like it was a kids toy. Good thing I buy lifetime warranty tools. Busted a 1/2" ratchet, and a breaker bar trying to pop a nut that was on for less than a year. 3/4" dr bar and socket took the abuse.

 

If/when you have time might as well do both

 

I have a breaker bar and extensions. Just bought at 36mm socket as well. Unfortunately it started pouring before I could get everything apart.

Yes, that is the plan.