Grinding/vibration/rumble Noise at ~30mph

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FormerTexan

Discussion Starter · Sep 9, 2015 (Edited by Moderator)

Band new Trailhawk Renegade with ~ 550 miles. When driving at a steady throttle input at about 30 mph a grinding noise starts and then it appears to go away as you speed up, you can actually feel it, like very faint rumble strips. The noise remains when I put the transmission in neutral and let the car coast. Sometimes it will stick around and give a grind down sound as you stop.

This was posted in another section and I'm thinking it's the same issue;

http://www.jeeprenegadeforum.com/fo...enegade-already-having-issues.html#post268426

The noise does seems to go away when switched into 4WD Lock. I haven't tried, but I will try next time I'm out slipping the car into manual from automatic and see what that does.

Any ideas? I'm thinking it is the transfer case.. Normal or should we take it into the shop?

Thanks!!!

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rsanges

· #2 · Sep 9, 2015

I've got the same issue on my TH (3/15 build date). I've posted in that other thread you linked to, but it would be nice to start one dedicated to this. I plan on waiting until my first dealer oil change and see what they say. The sound (to me) is more annoying than worrisome.

Here's my take on it:
It sound and feels like a weak rumble strip. It is barley noticeable on coarse pavement as it is drowned out by tire noise. Above about 40 mph it is either gone or covered up by other noises. It does not matter if I've been driving for 5 minutes or 5 hours.

I can switch it on/off at will. It's only present in auto-shift and auto-4wd. If I lock 4wd or change to manual shift mode it goes away completely, or will never occur if left in those modes. If I leave it in auto and keep a steady throttle at 25-35 mph the noise/vibration will "switch on" after about 10 seconds. I'm sure I could time it's start with a stopwatch as it seems 100% repeatable on my normally traveled routes.

If it's making the noise/vibration, it will switch off if I either: shift to the manual-mode transmission gate, or lock the 4wd. Within 10 seconds of switching either back to auto the noise/vibration returns. Like clockwork - it switches on and off very abruptly. It is definitely something in the system switching something on/off.

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syzygy

· #3 · Sep 9, 2015

rsanges said:
I've got the same issue on my TH (3/15 build date). I've posted in that other thread you linked to, but it would be nice to start one dedicated to this. I plan on waiting until my first dealer oil change and see what they say. The sound (to me) is more annoying than worrisome.

Here's my take on it:
It sound and feels like a weak rumble strip. It is barley noticeable on coarse pavement as it is drowned out by tire noise. Above about 40 mph it is either gone or covered up by other noises. It does not matter if I've been driving for 5 minutes or 5 hours.

I can switch it on/off at will. It's only present in auto-shift and auto-4wd. If I lock 4wd or change to manual shift mode it goes away completely, or will never occur if left in those modes. If I leave it in auto and keep a steady throttle at 25-35 mph the noise/vibration will "switch on" after about 10 seconds. I'm sure I could time it's start with a stopwatch as it seems 100% repeatable on my normally traveled routes.

If it's making the noise/vibration, it will switch off if I either: shift to the manual-mode transmission gate, or lock the 4wd. Within 10 seconds of switching either back to auto the noise/vibration returns. Like clockwork - it switches on and off very abruptly. It is definitely something in the system switching something on/off.

If it is missing in 4 lock it may be something to do with the rear axle disconnect. A grinding noise can never be good.

rsanges

· #4 · Sep 9, 2015 (Edited)

syzygy said:
If it is missing in 4 lock it may be something to do with the rear axle disconnect. A grinding noise can never be good.

My noise could never be described as "grinding". That's why I feel okay waiting it out until it's broken, or I take it in for an oil change.

Why, would you guess, it goes away in manual shift mode? Is 4wd locked in manual shift mode too?

syzygy

· #5 · Sep 9, 2015

rsanges said:
My noise could never be described as "grinding". That's why I feel okay waiting it out until it's broken, or I take it in for an oil change.

Why, would you guess, it goes away in manual shift mode? Is 4wd locked in manual shift mode too?

The op said it was not present in 4 lock.

FormerTexan

Discussion Starter · #6 · Sep 9, 2015

syzygy said:
The op said it was not present in 4 lock.

I just took it for a quick drive... it's very difficult to describe a sound

... it's more like rumble strips than a 'grind' sound, but you can feel it. My sound/rumble does not go away when I put the shifter into manual mode or into neutral.

syzygy

· #7 · Sep 9, 2015

FormerTexan said:
I just took it for a quick drive... it's very difficult to describe a sound ... it's more like rumble strips than a 'grind' sound, but you can feel it. My sound/rumble does not go away when I put the shifter into manual mode or into neutral.

You said "The noise does seems to go away when switched into 4WD Lock."

FormerTexan

Discussion Starter · #8 · Sep 9, 2015

syzygy said:
You said "The noise does seems to go away when switched into 4WD Lock."

That's correct, the sound subsides when switching into 4wd Lock.

syzygy

· #9 · Sep 9, 2015

FormerTexan said:
That's correct, the sound subsides when switching into 4wd Lock.

Then perhaps it is something to do with the rear axle disconnect mechanism.

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raz-0

· #10 · Sep 10, 2015

Hmm. 4 cylinder engines have a beat tone/frequency to them. This can cause vibration as the sound impulse is really powered by the combusting fuel, so the energy input is pretty significant. It seems the renegade/2.4/9speed combo puts that beat just above the target efficient RPMs. I have noticed this slightly boomy slightly grumbling sound since day 1. Putting it in a forced 4wd mode elminates it because it loads up the engine quicker, which means that where the beat tone happens is moved. Since it seems to go away, I'm assuming it is moved to something between idle and ~1500rpm which is a span the revs move through pretty quickly.

I suspect 1.4T engines and the over seas offerings don't have this issue because they don't get this drivetrain combination.

The AWDF system with it clutches is also kind of noisy. Similar to late 90s audis with torsen diffs.

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Tony Nesavich

· #11 · Sep 11, 2015

We are seeing the exact same thing. ... Thinking of invoking the lemon law. We had our computer flashed with an upgrade which helped slightly but it is still there.

Curious to know if you have seen any improvement.

raz-0

· #12 · Sep 11, 2015

Tony Nesavich said:
We are seeing the exact same thing. ... Thinking of invoking the lemon law. We had our computer flashed with an upgrade which helped slightly but it is still there.

Curious to know if you have seen any improvement.

I think you may have an issue invoking the lemon law for a noise if it doesn't actually impair the use of the vehicle.

For the folks complaining, it might be useful to post audio or video with sound to describe what you mean.

It's not like the engine is a particularly refined piece of work in this vehicle.

Tony Nesavich

· #13 · Sep 11, 2015

Vibration / Rumbling when slowing

2015 renegade/2.4/9 speed. Seeing lots of posts on this.

This one is particularly telling.
http://blog.caranddriver.com/jeep-r...ms-may-or-may-not-be-related-to-9-speed-auto/

We have been to the dealership 3 times. Class action is likely. At the very least we are invoking the lemon law. Anyone else have any feedback on if a fix is eminent or it is best to proceed with lemon lawsuit?

nesav132

· #14 · Sep 11, 2015

My Latitude is doing the same thing, been to the dealer 3 times and they don't know what it is. They flashed the computer, and did acknowledge they heard and felt it. It's more of a rumbling noise than anything. I can make it stop by putting it in "manual" mode.

R3N3GAD3

· #15 · Sep 11, 2015

Makes me glad I went with the manual transmission. Sorry this is happening for you 9spd auto folks.

bwbike

· #16 · Sep 11, 2015

That article was from May. Only a few people have had bad luck with their cars while many have not had any problems at all.

codev

· #17 · Sep 11, 2015

Try shifting down with the manual mode. Our "vibration" was actually caused by the Renegade slowing all the way to 0MPH in 2nd gear. If we tried that in 1st, the grittyness was gone. Not sure why, but the rumbling always coincided with 2nd gear to full stop.

raz-0

· #18 · Sep 11, 2015

If you are complaining about a noise, you might want to post an example.

The driveline in the renegade is not super quiet. There's a difference between not liking something and it being broken.

Without an example, we can't tell if you are complaining about something actually wrong, or just about the way the car is.

If the car isn't actually broken, good luck with the lemon law attempt. There are usually requirements to be met regarding the nature of an issue. Simply not liking the way the vehicle sounds probably doesn't make the cut.

Reactions: 1

JoeDahero

· #19 · Sep 14, 2015

Hey all. First post here though I'm a member over at JeepForum as well. Bought my TH in July. Tired of freezing my buns off in my '74 CJ5 during Colorado winters. 05/15 birthdate. Haven't had any "issues" so far but I have noticed this same hard to describe noise if what I'm hearing is the same thing. I notice it most when I'm decelerating for a stop below 30 mph. "Grinding" is not a good description of it but there isn't anything better. If I didn't know better I'd say it sounded like deceleration exhaust note but that isn't it. And it seems to be intermittent. I believe it has something to do with the traction control system as it goes away if I turn off the system. In fact I can be hearing it and press the button and it immediately stops. Anybody else have this same experience? Other than that I've logged about 2600 miles and have had no other issues. The noise doesn't seem to be impacting anything else so I'm taking the same approach as others in asking the dealer at the first oil change. No impact on fuel mileage as I'm averaging 20-21 in town. Just got home this evening from a trip over the mountains to the west side of the state and averaged 27 mpg both to and from (four adults and gear loaded, AC on, over the continental divide from 6000' up to about 10k'). Interested in others experiences and if anyone gets a confirmed answer at some point.

Joe

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Going Commando

· #20 · Sep 14, 2015

I experience what I would consider some low frequency gear grumbling or whining (to be more specific) when slowing down sometimes. When I flip the shifter to manual mode, the transmission is either in 5th or 3rd when the noise/feeling is occurring. While I don't suspect anything is wrong, it's was definitely concerning to hear/feel the first. I'm used to it now though.

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