Help me troubleshoot this noise

[TJMexico]

So, here's my first question to the forum as a Jeep newbie. It's noise related and while I know that accurately diagnosing a noise over the Internet is pretty much impossible, I'll give as detailed an description as I can and hope to maybe get some pointers. Ultimately, I'm hunting down the issue, but maybe I can get some guidance based on the cumulative experience of this forum. I will give as much detail as I can in hopes that maybe somebody might be able to give me ideas. I'm up in the mountain village right now without any way to really check this out. I hope to head back into the city soon where I can dig into the issue better. I hope I'm not just creating noise here.

The Jeep's specs are:
>2005 model X
>4.0l engine
>4-SPD. AUTOMATIC 42RLE TRANSMISSION
>DANA 30/186MM FRONT AXLE
>DANA M35/194MM REAR AXLE w/ TRAC-LOK DIFFERENTIAL
>Not certain of the transfer case designation yet. Assuming it goes with the transmission?

I have had the Jeep for about two weeks. It has kind of a rattling/rumbling noise coming from under the front end - almost like metal rattling. At first I thought it was brake related; the pads were badly worn. I fixed that (new calipers, new pads, turned the discs, etc.), but the noise didn't go away.

Recently had the tires rotated and balanced and the front end aligned. Replaced bushings on the control arms, but beginning to think maybe I should have just replaced the control arms completely. That's another topic, though.

I have never experienced any death wobble. The Jeep seems to handle well on the highway, and I have not had problems off road, either. 4wd works fine.

The sound doesn't change much with speed though it perhaps gets a bit louder. When I brake it goes away. It does seem to dissipate at about 40km/h or 25m/h. Above 50km/h or 30m/h it is barely noticable. Maybe the frequency just change there and it just blends into the other noises. Not sure. I simply do not hear it much past that speed and it's pretty much undetectable on the highway.

It does the same in all three drive modes and when I coast in neutral. Does it in reverse, as well. The sound does not change in any of those scenarios. It only makes the noise when I am in motion, not parked and idling.

When I brake, the noise disappears.

I have had four mechanics look at it.
1. The first one was stumped.
2. The second one put it on a lift with me in it, and I put it in drive. He said he thought it was the transfer case. He sent me to a shop that specializes in 4wd.
3. The third shop - the 4wd shop - went for a test drive and said the he didn't think it was the transfer case.
4. The fourth one thinks it's tire noise. The tires are very unevenly worn due to poor alignment from the P.O. and would certainly be making some strange noises, different from normal off-road tire noises, but when I get on dirt, sand or gravel, the noise continues unchanged, so I doubt tire noise.

I have a few ideas, but am wondering if there is any wisdom here that might help me out. Likely, it'll b a matter of elimination and I may be grasping at straws here, but asking doesn't hurt. Don't flame me. I'm still wet behind the ears.

My thoughts go to:
1. U-joints, either front drive shaft or axles. (I plan to to change these anyway as soon as I can, so that might eliminate the issue.)
2. Transfer case. (Not sure if there is a chain drive or direct gears in this one.) This is the one that scares me. Paid almost $10,000usd for the thing, hoping I don't have to spring for a transfer case.

Of course, if I just turn the music up real loud, the noise goes away. A little Willie and Waylon go along way to making things better!

 

[GregBelleville]

Have you looked at the wheel bearings?

You could pull the front driveshaft and see if the noise goes away.

 

[Moglocker]

So, here's my first question to the forum as a Jeep newbie. It's noise related and while I know that accurately diagnosing a noise over the Internet is pretty much impossible, I'll give as detailed an description as I can and hope to maybe get some pointers. Ultimately, I'm hunting down the issue, but maybe I can get some guidance based on the cumulative experience of this forum. I will give as much detail as I can in hopes that maybe somebody might be able to give me ideas. I'm up in the mountain village right now without any way to really check this out. I hope to head back into the city soon where I can dig into the issue better. I hope I'm not just creating noise here.

The Jeep's specs are:
>2005 model X
>4.0l engine
>4-SPD. AUTOMATIC 42RLE TRANSMISSION
>DANA 30/186MM FRONT AXLE
>DANA M35/194MM REAR AXLE w/ TRAC-LOK DIFFERENTIAL
>Not certain of the transfer case designation yet. Assuming it goes with the transmission?

I have had the Jeep for about two weeks. It has kind of a rattling/rumbling noise coming from under the front end - almost like metal rattling. At first I thought it was brake related; the pads were badly worn. I fixed that (new calipers, new pads, turned the discs, etc.), but the noise didn't go away.

Recently had the tires rotated and balanced and the front end aligned. Replaced bushings on the control arms, but beginning to think maybe I should have just replaced the control arms completely. That's another topic, though.

I have never experienced any death wobble. The Jeep seems to handle well on the highway, and I have not had problems off road, either. 4wd works fine.

The sound doesn't change much with speed though it perhaps gets a bit louder. When I brake it goes away. It does seem to dissipate at about 40km/h or 25m/h. Above 50km/h or 30m/h it is barely noticable. Maybe the frequency just change there and it just blends into the other noises. Not sure. I simply do not hear it much past that speed and it's pretty much undetectable on the highway.

It does the same in all three drive modes and when I coast in neutral. Does it in reverse, as well. The sound does not change in any of those scenarios. It only makes the noise when I am in motion, not parked and idling.

When I brake, the noise disappears.

I have had four mechanics look at it.
1. The first one was stumped.
2. The second one put it on a lift with me in it, and I put it in drive. He said he thought it was the transfer case. He sent me to a shop that specializes in 4wd.
3. The third shop - the 4wd shop - went for a test drive and said the he didn't think it was the transfer case.
4. The fourth one thinks it's tire noise. The tires are very unevenly worn due to poor alignment from the P.O. and would certainly be making some strange noises, different from normal off-road tire noises, but when I get on dirt, sand or gravel, the noise continues unchanged, so I doubt tire noise.

I have a few ideas, but am wondering if there is any wisdom here that might help me out. Likely, it'll b a matter of elimination and I may be grasping at straws here, but asking doesn't hurt. Don't flame me. I'm still wet behind the ears.

My thoughts go to:
1. U-joints, either front drive shaft or axles. (I plan to to change these anyway as soon as I can, so that might eliminate the issue.)
2. Transfer case. (Not sure if there is a chain drive or direct gears in this one.) This is the one that scares me. Paid almost $10,000usd for the thing, hoping I don't have to spring for a transfer case.

Of course, if I just turn the music up real loud, the noise goes away. A little Willie and Waylon go along way to making things better!

Take out the driveshafts one at a time,that will tell you what axle it’s on.i had a noise that went away when I pressed the brakes,it ended up being a bad caliper on the left rear.

 

[TokenJo]

Good write up. A couple things:
- how many miles on it?
- does it make the sound when 4wheel is engaged?
- jack the front end up and grab tires side to side and top and bottom and shake, should get a little play or may hear some clunking which would make think a wheel bearing.
- also there are 12-13 grease points on the jeep. Front/Rear suspension joints and ujoints. Sometimes people do not lube for regular maintenance and can cause noise.

Welcome to the forum, good advice on this site. Hope you're able to get if figured out.

 

[TJMexico]

Good write up. A couple things:
- how many miles on it?
- does it make the sound when 4wheel is engaged?
- jack the front end up and grab tires side to side and top and bottom and shake, should get a little play or may hear some clunking which would make think a wheel bearing.
- also there are 12-13 grease points on the jeep. Front/Rear suspension joints and ujoints. Sometimes people do not lube for regular maintenance and can cause noise.

Welcome to the forum, good advice on this site. Hope you're able to get if figured out.

Thanks.

In answer to your questions:
>Just turning over 100,000 miles. (Actually, just turned over 160,000km yesterday, which is just under 99,500 miles.)
>Yes, makes the sound in a modes, even when coasting in neutral and in reverse.
>Wheel bearings have been checked, they are good.

As to grease points, I have only had it for about two weeks, so I have no idea, but my guess is that the P.O. didn't do that. I'll get under it and check that out.

I am leaning toward axel u-joints, will swap those out as soon as I can.

 

[Cooper Smith]

Thanks.

In answer to your questions:
>Just turning over 100,000 miles. (Actually, just turned over 160,000km yesterday, which is just under 99,500 miles.)
>Yes, makes the sound in a modes, even when coasting in neutral and in reverse.
>Wheel bearings have been checked, they are good.

As to grease points, I have only had it for about two weeks, so I have no idea, but my guess is that the P.O. didn't do that. I'll get under it and check that out.

I am leaning toward axel u-joints, will swap those out as soon as I can.

Suggestion, post a video of it on YouTube and link it here. Makes it more identifiable.

You most likely have a NP231J transfer case.

 

[JKP]

Remove the front DS, this will eliminate it, and it will also prevent the wheels from turning the DS which turns the chain in the tcase.

You can drive with it out for as long as you want.

With the shaft still out, you can put it in 4WD and this will engage the chain in the tcase.

If all stock, it's a NP231 tcase.

 

[TJMexico]

Thanks for all the input...

 

[TJMexico]

Remove the front DS, this will eliminate it, and it will also prevent the wheels from turning the DS which turns the chain in the tcase.

You can drive with it out for as long as you want.

With the shaft still out, you can put it in 4WD and this will engage the chain in the tcase.

If all stock, it's a NP231 tcase.

So, as I understand, if I remove the front drive shaft and run in 2wd, the transfer case will remain in neutral and will not spin. If the noise continues in 2wd, it is definitely in the axle u-joints. (I've checked the bearings and they are good.) If it does not but sounds when I engage the tranfer case, then the issue is there.

Sounds good. Thanks!