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Rear rotational knock from differential at low speeds.

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If anyone gets a chance to jack up their vehicles to post a video of said noise please do. So we can add your issue to our lists. Thanks for any input you may offer. We are not super concerned or trying to stir a pot per say we are just attempting to get to the bottom of either what may be normal or if what may eventually become a problem.
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We can only get the noise to happen directly at 3mph while off the ground. It’s very weird. And now seems as if it’s only a rotating vibration noise that is only traversing up to the inside rear cabin area but yet outside the vehicle, it sounds as if it’s coming from inside the area behind the passenger side tail light. We give up on what it is.
 

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We can only get the noise to happen directly at 3mph while off the ground. It’s very weird. And now seems as if it’s only a rotating vibration noise that is only traversing up to the inside rear cabin area but yet outside the vehicle, it sounds as if it’s coming from inside the area behind the passenger side tail light. We give up on what it is.
Interesting
 

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Interesting observations. From reading the forum I was under the impression that the rotational knocking was occurring only on D44 axles with limited slip differentials.

This is the first that I’ve heard (that I remember anyway) where Rubicon D44 axels with open differentials and lockers have had the noise.
 
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This is the exact noise we heard on multiple vehicles with the Dana 44 rears. It’s the sound of like a military helicopter off in the distance. It’s rotational, but only on passenger side rear. It’s very strange, and once again the vehicle is going exactly 3mph.



 

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Interesting observations. From reading the forum I was under the impression that the rotational knocking was occurring only on D44 axles with limited slip differentials.

This is the first that I’ve heard (that I remember anyway) where Rubicon D44 axels with open differentials and lockers have had the noise.
We’ve only found this happening on Dana 44’s. Inside the vehicle you would swear it’s from the rear axle cause you hear it coming from directly below the rear center floor sub on the 2 dr. But outside the vehicle, now being under a few different jeeps and taking my rear apart we only hear it making that noise right where we have it pictured. But yet it’s got to be coming from the passenger side of the rear pumpkin and transferring to this one spot behind the light.
1. On ground it will show itself between 2-5 mph
2. Off the ground it will only happen at 3mph.
3. 2H or 4H or 4L it does not matter.
We did just notice on another vehicle that the sound is more audible on one that does not have the rear subwoofer. Hmmm.....
 

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Here's what I had happening in mine. Sounds exactly the same as the OP's video, but was much louder.

Axle was replaced, hoping for the best.
 

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This is the exact noise we heard on multiple vehicles with the Dana 44 rears. It’s the sound of like a military helicopter off in the distance. It’s rotational, but only on passenger side rear. It’s very strange, and once again the vehicle is going exactly 3mph.



I DEFINITELY would notice that on my vehicle. I have the LSD D44 between 33s and do not have that noise. I have driven it up to 80 MPH for miles; I crawl through my yard at 2-3 MPH. I have done some light trails and off-roading - 3500+ miles. Just letting you know that there IS hope that you can have this setup without that problem.
 

bwright1818

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I have the thumping sound that sounds like the OP's description of a military helicopter in the distance. That is a very good description of the sound. A rapid, deep, "wump, wump, wump." Since this post started, however, I have been more aware of it and find it happens at more than one speed, mostly on deceleration and more to the right rear of the vehicle than the center, to my ears. If I had to guess what it was, independent of this thread, I would say it is a harmonic vibration of some kind, in the body or exhaust...Hard to say by myself, though.
 

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2018 JLU Sahara with D44 Limited Slip and 13xxx miles. NO Knocking noises from rear during slow speed/coasting. I had a RWD with sloppy spider gears in the carrier before that made the knock so I definitely know what that sounds like. Swapped that entire axle out to fix.
 

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I have had a similar experience with my 2018 JLU Sport V6 with LSD and manual trans. I notice it more if I take off from a full stop ( limit slipping the clutch). It sounds a lot like drive line slack. I’ve tried to see if I can baby my take offs from a stop. Still happens intermittently. It happens even more when taking off from a stop on a hill. It can be extremely loud. You can even feel it in your seat. I was going to have the dealership look at it when they perform other Warranty work (Radio Died). I’ll let you know what they say. Worst case is that it will definitely be documented.

I find it hard to believe that Jeep would blow this issue off.... Especially when so many customers are experiencing this issue. If it is normal, they would probably post a service message. The more customers that identify this issue, the more likely they will perform a suitable fix.
 

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I had the knock on my 2.0 Sport. I put on bigger tires and it's gone. Same set of scenarios.

**Edit no LSD Standard Dana axels
 

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My Jeep intermittently makes a click/rattle sounding noise while driving when I let off the gas slowing down in lower RPMs (usually 1,000-1,500) that sounds like it's coming from the driver side lower area of the engine bay. I had it checked out twice by two different dealerships. The first dealership said that it was "turbo noise" and was normal which I didn't think was correct because the noise isn't even coming from where the turbo is located on the Jeep. The second dealership said that it was related to the differential, was normal, and that a cover muffling the noise to the cabin has fallen because a grommet fell off. Since the grommet/cover was fixed, I can no longer hear the noise inside the cabin. Usually I only hear it when my doors are off. Either way, I was told that the noise is completely normal, and I have been driving it with it making that noise since January (over 10,000ish miles). Now I'm curious if it's actually related to the differential or not.
 
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I gave up on my 2018 2dr sport s with the d44 last night. Jeep is now gone, Sold it back to the dealership. Not sure what we’re going to buy now but it sure as hell won’t be any of these FIAT Jeeps.
 

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I gave up on my 2018 2dr sport s with the d44 last night. Jeep is now gone, Sold it back to the dealership. Not sure what we’re going to buy now but it sure as hell won’t be any of these FIAT Jeeps.
To bad about your troubles, this type of stuff is annoying at times. Opinion wise your move to get rid of your jeep seems a little mis-proportioned. If the sound you were hearing was the same as mine then with a little homework on your part to learn as much about the operation of the rear diff and the problems others were experiencing mixed in with patience and help from JeepCares / FCA ECS you might be on your way to a problem fixed.

If your unable to get under your jeep or unwilling to then your path seems appropriate.

Any dealership willing to let you test drive their inventory of Jeeps to check out the noise of the drive line should have been helpful enough to look into your noise issue in greater depth though and come up with a solution you would be happy with.

My 2018 has the noise https://www.jlwranglerforums.com/forum/threads/knock-in-rear-with-dana-44.16921/page-40#post-853552
However the wife's 2019 is noise free and mechanically smooth as silk. Will it stay that way?, possibly not but now with the 2018 on its way to being repaired we both know exactly what to listen for and when it happens.

Regards and good luck with your next ride.
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