Strange noise in rear - JeepForum.com
 
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post #1 of 10 Old 05-28-2020, 03:15 AM Thread Starter
dariok
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Strange noise in rear

Hello,

I have had a problem for a long time and I can't figure out a solution

It appears in specific moment when I go uphill and turn right it sound like hooting accompanied with knocking (knocking not loud as hooting). The sound comes from the rear end and the person sitting behind the driver feels the vibrations underfoot. It does not always appear, but only when the accelerator pedal is pressed harder, when there is more effort for the car.

Changed rear axle bearing, checked diff fluid it is okay (changed half year ago), change wheel bearings.

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post #2 of 10 Old 05-28-2020, 07:12 AM
Bigrigr
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Check the upper control arm in the rear. Look for a loose balljoint at the axle, and loose bushings where the control arm bolts to the frame. Also check the lower control arm bushings as well.

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,4" short arm lift,JK'sW/32's
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post #3 of 10 Old 05-28-2020, 07:34 AM Thread Starter
dariok
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Quote:
Originally Posted by Bigrigr View Post
Check the upper control arm in the rear. Look for a loose balljoint at the axle, and loose bushings where the control arm bolts to the frame. Also check the lower control arm bushings as well.
Changed bushings on rear upper control arm about 7 months ago. Ball joint checked its good. Now is changed lower control arm bushings.
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post #4 of 10 Old 05-28-2020, 08:01 AM
helijeeper
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Could you describe the hooting? Like an owl?

Do you have 4 wheel drive? Select Trac? Quadradrive?

What speeds does this happen?


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post #5 of 10 Old 05-28-2020, 08:07 AM
BeignetatBeach
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and please validate your u-joints!
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post #6 of 10 Old 05-28-2020, 08:33 AM Thread Starter
dariok
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Quote:
Originally Posted by helijeeper View Post
Could you describe the hooting? Like an owl?

Do you have 4 wheel drive? Select Trac? Quadradrive?

What speeds does this happen?


Sent from my SM-N960U using Tapatalk
Yes similar to an owl, but only deeper and lasts a few seconds depending on the effort (if the car needs to overcome a stronger curve then it lasts longer). It mostly happens at lower speeds.
Transfer case is NP242 (Select trac) and I got this strange sound in 2WD and in 4Lo.
Here is one case where I had in 4Lo. I climbed uphill and went slightly to the right that I had that sound for about 10 seconds.
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post #7 of 10 Old 05-28-2020, 09:06 AM
Bigrigr
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What is the condition of the rear diff fluid? Is it full and clean? What are the chances that you have a limited slip diff that needs a fluid change and friction modifier added? The clutches in these limited slip diffs make some weird noises when they need friction modifier

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,4" short arm lift,JK'sW/32's
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post #8 of 10 Old 05-28-2020, 10:16 AM
coldspit47
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I would guess spiders, to be honest - possibly due to improper lubrication or FM, but that howl/hoot is a telltale sign the diff is on its way out. Paired with that, knocking to me sounds like spiders slipping or binding against ring gear. With a D44 you have a good chance of vari-lock, which needs that FM. Did you find any shavings in the diff fluid when you changed it? How did the ring, pinion, and spider gears look?

04 WJ NV242, IRO 3in, bilsteins, IRO adj UCAs/LCAs/A arm, 265/75/16 Laufenn Xfit, 4.56 gears
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post #9 of 10 Old 05-29-2020, 02:22 AM Thread Starter
dariok
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Mopar Friction Modifier was added. Diff fluid color is like dark gold.

When my brother changed the oil he found shavings but not too much. On some gear it can be seen that they are worn out (their tops are not straight but rounded).

But I dont know why only this problem appears only in this case
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post #10 of 10 Old 05-29-2020, 07:17 AM
Bigrigr
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If you have mismatched gear faces, then something is going on there. Need to pull those spider gears out and get a better look. The spider gears are turning when the Jeep is turning, thus causing the noise only when you turn right.

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,4" short arm lift,JK'sW/32's
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