Rear End Rumble

[matchframe]

I have been trying to find out what the rumble noise is from the rear axle. I replaced the wheel bearings, rear U-joint and rotated the tires.

Kermit is a '97 XJ that has the Chrysler 8.25 rear end.

What is left to make a rumble noise from the rear axle, the pinion bearings?

How hard is it to replace those?

[GoneWithTheWind]

Could be the pinion shaft or the ring and pinion gears. Getting the yoke off can sometimes be a pain. If you did your bearings, you should be able to do the work you need. The spider gears can be tricky.

[matchframe]

Could be the pinion shaft or the ring and pinion gears. Getting the yoke off can sometimes be a pain. If you did your bearings, you should be able to do the work you need. The spider gears can be tricky.

If it is the ring and pinion gears, would I need to replace the gears? Or is there a bearing other than the pinion shaft bearing in there that can be replaced?

[GoneWithTheWind]

The ring and pinion get wore out like everything else. The only way to check is to pull the cover off to make sure that is the problem. The gears should have clean edges, not chipped or rounded. Is the noise a grinding sound or something like a stuck pig?

[GoneWithTheWind]

If your u-joint was really bad, it could have affected your pinion shaft.

[GoneWithTheWind]

That's about as far as I can help you. There are smarter people that can take it from here. :)

[matchframe]

If your u-joint was really bad, it could have affected your pinion shaft.

The noise is more of a rumble sound. It increases and decreases with speed. The u-joint was actually in pretty good shape but since I had already bought a replacement I went ahead and replaced it. While I had the Jeep up on jack stands, I ran it in gear so I could try to pin point where the noise was coming from. To me it sounded like it was around the input shaft of the differential.

[4.3LXJ]

Getting in on this late. So a couple of questions. First, was the bearing surface on the axle galled? If so, new bearings will not fix that. Second, does the sound disappear under acceleration or deceleration?

[Pinkyman]

Are you lifted? I had a noise that sounds identical to that when I initially put my lift in.

[matchframe]

Getting in on this late. So a couple of questions. First, was the bearing surface on the axle galled? If so, new bearings will not fix that. Second, does the sound disappear under acceleration or deceleration?

The axles looked smooth and clear. No surface indication of bearing problems. The noise is there during acceleration and deceleration. Pretty much any time the Jeep is moving I hear the rumble.

[matchframe]

Are you lifted? I had a noise that sounds identical to that when I initially put my lift in.

No lift, stock height.

[4.3LXJ]

If you shift into neutral and coast does it change?

[matchframe]

If you shift into neutral and coast does it change?

Not sure but can take it out for a quick drive and find out. Be right back...

[matchframe]

The rumble noise is there whenever the Jeep is moving. I hear it when accelerating and decelerating as well as coasting in neutral.

I am uploading a short video to my photo bucket account and as soon as it is ready I will post it. The audio on the video does not do it justice but you can hear what it sounds like.

[matchframe]

Ok here is the video for audio of what it sounds like. About 30 seconds in I turn onto the feeder road and accelerate to about 50mph then pop it into neutral to coast. This audio really does not do justice to what it really sounds like. Click on the thumbnail below:

http://i10.photobucket.com/albums/a122/matchframe/BDG/th_009_zps2faro4yl.mp4 (http://i10.photobucket.com/albums/a122/matchframe/BDG/009_zps2faro4yl.mp4)

[4.3LXJ]

I think based on everything so far that you have a wheel bearing problem. Since you replaced the bearings, it is not the end of the world as long as they are lubricated. If it was gears, the noise would disappear if you accelerate or decelerate. If pinion bearings, the same whether under power or not. But if just coasting, that generally means a wheel bearing and the vid kind of sounds like it

[matchframe]

I think based on everything so far that you have a wheel bearing problem. Since you replaced the bearings, it is not the end of the world as long as they are lubricated. If it was gears, the noise would disappear if you accelerate or decelerate. If pinion bearings, the same whether under power or not. But if just coasting, that generally means a wheel bearing and the vid kind of sounds like it

That makes sense. So should I replace the bearings again? Maybe a higher quality bearings? What would you recommend for a bearing brand? Or maybe replace the axles as well?

[4.3LXJ]

You would have to replace the axle or axles and bearings

[matchframe]

You would have to replace the axle or axles and bearings

Ok. Any recommendations on axle brands and where to get them?

Thanks !

[4.3LXJ]

Timken bearings are always good

[BlackYeti]

Front CV shaft? Just throwing it out there. Real simple to pull it off and double check the sound.

[Mudderoy]

You would have to replace the axle or axles and bearings

Why axles?

[4.3LXJ]

Why axles?

The axle surface acts as a bearing surface since the bearing has no inner race. When the axle gets galled, the bearing will be noisy even if you replace the bearing. There is a thing called an Axle Saver Bearing, which is an outer race with an offset inner bearing but I couldn't find one for the 8.25. It was invented by a friend of mine and fellow Jeeper who owned Mac's Jeep Parts. More on that in another post

[matchframe]

I put the Jeep up on jack stands where I could listen from underneath while it was idling in gear. I made sure it was all safe and I did not get all the way under. I could tell that the noise was originating at the gears (middle of the axle). My belief is that it is probably one or both of the main bearings that the ring gear is on. I listened with a stethoscope behind each wheel where the wheel bearing are and it was quiet at both wheels. The noise was centered at the pumpkin.

So I dug out the rear end I pulled from the '99 Cherokee and started cleaning it up. It is a Chrysler 8.25 as well only this one is a posi-trac. The one on Kermit is a uni-trac. Glad that rear end did not sell when I was trying to sell it !!

So hopefully I can replace the rear end in the next week or so. I will update with that if there is interest.

http://i10.photobucket.com/albums/a122/matchframe/BDG/IMG_7537_zpsz1eatqwx.jpg