Grinding/rumbling noise around 40mph

[Lucky]

Hi all,

Has anyone else experienced a grinding/rumbling noise from the rear of the car at around 40 mph / 60km/h? It's a well known problem with the Renegade, but I can't find anything about it here. Perhaps I'm not looking good enough.

The noise is present at temperatures above 5-6 degrees Celcius, with gearbox and driving mode in auto. It's often also a vibration that I can feel through the floor. The noise immediately disappears when I change to manual gearshifts or select another driving mode. With the Renegade it doesn't seem to matter what engine/gearbox you have, it's present at all models. I have a 1,4 170hp 9AT. The theory amongst Renegade-owners seems to be that it's related to a clutch in the rear differential. I think that might be correct, it's plausible that a clutch that's not completely releasing the centre axle can be the origin of the noise. But I believe that the actual noise is a resonance of some sort. Any experience with this problem?

The dealer has no idea what the problem is, but they recognize that there is a noise/vibration.

[5port]

Hi all,

Has anyone else experienced a grinding/rumbling noise from the rear of the car at around 40 mph / 60km/h? It's a well known problem with the Renegade, but I can't find anything about it here. Perhaps I'm not looking good enough.

The noise is present at temperatures above 5-6 degrees Celcius, with gearbox and driving mode in auto. It's often also a vibration that I can feel through the floor. The noise immediately disappears when I change to manual gearshifts or select another driving mode. With the Renegade it doesn't seem to matter what engine/gearbox you have, it's present at all models. I have a 1,4 170hp 9AT. The theory amongst Renegade-owners seems to be that it's related to a clutch in the rear differential. I think that might be correct, it's plausible that a clutch that's not completely releasing the centre axle can be the origin of the noise. But I believe that the actual noise is a resonance of some sort. Any experience with this problem?

The dealer has no idea what the problem is, but they recognize that there is a noise/vibration.

The only rumbling I get on my 2.4L 2016 is when the engine upshifts to 8th and I'm cruising at 1600 rpm. Since new.

Someone with 26K miles just had his rear wheel bearings replaced which can sound like grinding.

[FiatCares]

Hi all,

Has anyone else experienced a grinding/rumbling noise from the rear of the car at around 40 mph / 60km/h? It's a well known problem with the Renegade, but I can't find anything about it here. Perhaps I'm not looking good enough.

The noise is present at temperatures above 5-6 degrees Celcius, with gearbox and driving mode in auto. It's often also a vibration that I can feel through the floor. The noise immediately disappears when I change to manual gearshifts or select another driving mode. With the Renegade it doesn't seem to matter what engine/gearbox you have, it's present at all models. I have a 1,4 170hp 9AT. The theory amongst Renegade-owners seems to be that it's related to a clutch in the rear differential. I think that might be correct, it's plausible that a clutch that's not completely releasing the centre axle can be the origin of the noise. But I believe that the actual noise is a resonance of some sort. Any experience with this problem?

The dealer has no idea what the problem is, but they recognize that there is a noise/vibration.

Hello Lucky,
We are certainly sorry to hear about your current concern. If you could please clarify if you live in the United States this will help me determine how to best assist you moving forward.
Laura
FiatCares

[Lucky]

Hi Laura

I'm glad to hear Fiat cares. I live in Norway. Sadly there's very few 500x's in Norway, it's way too expensive as new (and cheap as used). That's why I'm trying this American forum to get some tips.

The problem is widely described here: https://www.jeeprenegadeforum.com/th...t-30mph.28737/

[Lucky]

The only rumbling I get on my 2.4L 2016 is when the engine upshifts to 8th and I'm cruising at 1600 rpm. Since new.

Someone with 26K miles just had his rear wheel bearings replaced which can sound like grinding.

The noise I have is quite similar to a bearing that is completely gone, but there is no faulty bearings to be found. Also, it's very strange that the noise is present when the center axle is supposed to stand still, but not when it's rotating. I suspect the axle isn't really standing still, next step is to mount a GoPro underneath the car to get some evidence. The noise is speed related, not engine rpm/gear related. I'm quite familiar with the sound of a broken wheel bearing, and I'm 100% sure that's not the cause. But thanks for the tip!

[HalfPint]

This has been a major issue and complaint on Jeep Renegades. I just figured it out and fixed it on mine, so I will post a link to the thread I made on the Renegade forum.

https://www.jeeprenegadeforum.com/th...37/post-945389

[5port]

This has been a major issue and complaint on Jeep Renegades. I just figured it out and fixed it on mine, so I will post a link to the thread I made on the Renegade forum.

https://www.jeeprenegadeforum.com/th...37/post-945389

That is a great tip. Thanks!

[HalfPint]

Over on the Renegade forum this has been a big issue, and there's a sticky thread on the topic with over 600 posts - yet my fix has not generate a single reply so far. So I think I'm gonna post the full copy here to make it easier to find for 500X owners:

booster.jpg

If you look at this cutaway image of the rear diff, you'll see the multi plate wet clutch on the right. These are interleaved friction discs, where every other one is connected to the ring gear & input shaft (lower left), and the others are connected to the differential.

The only difference in this assembly when the grinding noise is heard is that the input shaft & ring gear are stationary, and therefore every other disc in the clutch pack is stationary. When the input shaft is spinning there is very little speed difference between the discs. The noise cannot come from the input shaft or ring gear, or their bearing, because it happens when they are stationary. Therefore the noise comes from the clutch pack.

I noticed the other day that when the grinding noise occurs the entire floor resonates like a sounding board, yet the entire rear diff and suspension is attached to the chassis with rubber isolators/bushings. I figured that maybe the problem isn't that the diff is resonating/vibrating, but rather that the bushings have failed - just as the motor mounts fail and allow engine vibrations into the chassis. So I took a look underneath.

All of the rear subframe and diff support bushings seemed fine. That left the center driveshaft support to be examined, and it was a major suspect since it's connected to the rear diff input, and therefore to the clutch pack which must be the source of the vibration. Clearly there was also a mechanical resonance occurring. I noticed the drive shaft is light and that when shaken there was a rattle at the center support. If you gripped it solidly enough the rattle was damped out - but of course it must be able to spin. It was also really easy to move it around in the rubber bearing support, so I figured maybe if that rubber part were stiffer it would damp out that rattle.

I found that there is a fairly deep groove around the center bearing towards the front, and I was able to cut a piece of 5/16" fuel line to an appropriate length, and pack it into that groove. Took it for a drive and the groaning/growling vibration is gone.

Bushing.jpg
Tube.jpg

That was yesterday. We drove it going out to dinner last night and it was so much nicer to drive. It was a bit warmer today, and I realized I had a can of rubber cement for tire patches and the like which had a brush in the lid. I brushed it all around the tubing in the hopes that it will hold it in place. There really isn't much force trying to push it out,