Thrumming Noise at Highway Speeds (63-67ish)

ambrose

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I've had this JLUR since mid-January, and I finally took it into the dealer about a month ago. The problem is when hitting around 63mph and until around 67mph, there is a noticeable thrumming noise. Thrum.. thrum.. thrum. You can feel it through the steering wheel and hear it, if you have the top up and windows closed.

The dealer (Reedman-Toll in Langhorne, PA) kept it for a few days to do diagnostics. They said they put other wheels from a Sahara on the lot on, and it was still there. They re-balanced, and they said it was slightly less loud. (I think so, too, but still noticeable.) They also said that every other JL on the lot makes a similar noise, just that mine is louder.

They claim this is just how the JLs are. Seems wrong to me. I posted on another JL forum, and nobody said that they had heard it. Maybe @JeepCares has some thoughts on this? Is it a JLUR design flaw, perhaps?

It's a minor annoyance, but seems like it should be looked into.





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ambrose

ambrose

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Every time I hit those speeds.
 

JeepCares

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Hi ambrose,

We are sorry to hear that you have a concern with your Jeep. Please send us your VIN and mileage so that we can document this further on your behalf.

Darlene
Jeep Social Care Specialist
 

Kevin8086

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Yes it’s like a buffering noise? Like the windows are moving and creating a pressure difference inside the vehicle? I’ve had multiple people tell me they have the same thing. I just crack the window most the time.
 

JimL

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About what frequency and does it "cycle" intensity?

It is possible for a vehicle to have a cyclic drumming or vibration sound at the frequency of ECM "feedback" control. This occurs as torque changes slightly due to Air Fuel Ratio management by the engine computer. This would be noticeably cycling, about every second or so. I have seen cross-mounted muffler systems transmit the sound into a rear floor panel on various types of vehicles. Remember, the sound waves off the side of the muffler are moving air at a frequency, and a larger surface is able to absorb more of that energy.

That is not the only source of such a noise. I have seen radiator hoses that were hardened, or installed with a twist, or pulled too tight (short) that can transmit the changes of engine torque into the body. Remember....closed-loop feedback engine control changes the amount of torque due to the small air-fuel ratio change.

A thrumming noise that cycles intensity over a longer period of time can be caused by tire RFV that is responding to an opposite tire which is turning at a slightly different frequency. These conditions will usually run in 7-14 second periods of "more/less" noticeable intensity. This is a common condition on straight axles and peak vibration (not very high amplitude) typically occurs when the "peak" RFV spot on a tire is at 90 degrees, than 180 degrees, than 270 degrees to the peak point of the opposite side tire. You would be surprised how matching tires do not run at the same rotation speed. I have worked on "worst case" vehicles where we had to get specially selected tires to minimize the change period (we could stretch it out to over a minute or more, which is much less bothersome for the driver).

Sometimes tires can be tested on a wheel balancer with RFV measurement, and the condition can be improved by moving the tire on the rim (which can reduce the peak RFV in some cases). RFV measurements are in numbers and "13 is unlucky" meaning 13 or more is likely to be an unsatisfactory tire for straight axle applications.

Certain roads can exacerbate this condition, where there is small "pattern rippling" in the road surface. I was having some issues with my Rubicon on a few roads in our area. I did pretty much eliminate it by getting the tire pressures down to normal (hard to believe the dealer handed over the Jeep with 45 PSI in all four tires).

There is a lot more going on with "tire stuff" as you can see, and it gets more difficult when the tires are aggressive tread pattern. Try a test drive with about 30 psi in the tires...just to see if it is better or worse, and pay attention to the frequency within the thrum sounds.

Hope this helps, at least to understand some...….Jim
 

monsterpiece

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I've had this JLUR since mid-January, and I finally took it into the dealer about a month ago. The problem is when hitting around 63mph and until around 67mph, there is a noticeable thrumming noise. Thrum.. thrum.. thrum. You can feel it through the steering wheel and hear it, if you have the top up and windows closed.

The dealer (Reedman-Toll in Langhorne, PA) kept it for a few days to do diagnostics. They said they put other wheels from a Sahara on the lot on, and it was still there. They re-balanced, and they said it was slightly less loud. (I think so, too, but still noticeable.) They also said that every other JL on the lot makes a similar noise, just that mine is louder.

They claim this is just how the JLs are. Seems wrong to me. I posted on another JL forum, and nobody said that they had heard it. Maybe @JeepCares has some thoughts on this? Is it a JLUR design flaw, perhaps?

It's a minor annoyance, but seems like it should be looked into.

I have the exact symptom on my 2018 JLUR, it only happens around 61 to 67 mph. "Thrum.. thrum.. thrum" is really the best description of this vibration. It happens every single time when you are in this speed range. Feel like more noticable if your 8-speed tran is in the 8th gear and just cruising. When your hands are on the steering wheel, you definitely feel the vibration and you hear it too. My wife was sitting in the back seat said she did not feel it or heard it. This feels definitely different from the vibrations caused by unbalanced tires (I have had enough of bad experiences on that), in that case the vibration is constant in a speed range, but this vibration comes and goes every second or so, or 1-2 cycles per second. @JimL .


Hope Jeep would have a resolution to this problem.... Should I visit a jeep dealer?? Calling for @JeepCares !

Could this be the drive shaft out of balance? I remember a while ago, I heard something flew out from underneath the jeep and that thing hit the under body, now I am suspecting if it were a balancing weight on the drive shaft??

Also, around 50-55 mph, anyone feel some pressure waves and sounds in the cabin when windows closed and top on? Could it be the same vibration? I thought maybe it was some weird aerodynamic issue, only in that speed range....
 
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monsterpiece

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Went to dealer, they don't have open appointments for the next two weeks. Nice, isn't it. So I took the jeep to a local mechanic, he charged me 40 dollars for tire balancing. Now it is much better, but I have still heard the thrumming noises, but much lighter than before.
 

Hotlanta

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I'm interested to hear of any resolution for the vibration and noise, is this a tire design flaw or tire quality issue? I have 360 miles on my JLU Rubicon and am having the same issue from the first drive home and it's annoying given the sticker for my new jeep was over $55k. I noticed my tires were inflated to 42 lbs PSI and thought reducing to the factory recommended 37 would help. Only made the vibration worse/louder. Starts around 63 mph and up to 67 mph. Seems to be a tire issue that based on this thread is a common issue.

I just traded my 2013 JK Sahara Unlimited after a month in the dealer service and body shop due to an accident and the front drive shaft was dented causing a "similar" noise/harmonic vibration that was resolved with the new driveshaft. This issue started at ~60 mph and dropped off around 67 and then back again at 75+.
 

Yakpimp

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Is this the sound you hear? I also get this after getting my windshield replaced at the exact same speeds.

 

Hotlanta

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No, that sounds like an airgap/whistle. The issue I have is clearly is identical to what the other posters have described and is either a tire or drive train, drive shaft vibration at certain speeds.

Only reason I'm more focused on the tire is since I deflated 5 lbs to 37 PSI vs the 42 they delivered it with the vibration is worse. Makes me wonder if they deliver all JLURs' at higher PSI to mask the issue. I have the stock BFG tires.
 

Capt-Zoom

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I don't have the thrum unless I only have one back window open. Then I get the trrum, pressure waves and can feel it in my ears . Especially around 35mph . Weird.
 
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ambrose

ambrose

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This is definitely not a cabin air pressure issue.

The dealer said they swapped out the tires from a Sahara on the lot (diff tires from Rubi) and could still hear it. So I don't think it's the tires themselves. They did rebalance, and I did find it less loud. But it's still noticeable.

Jeep Cares suggested I take it to another dealer. I don't have much confidence right now, though. I'm just hoping enough people take to dealers to make it more of a thing they might actually address.
 

viper88

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I have the exact symptom on my 2018 JLUR, it only happens around 61 to 67 mph. "Thrum.. thrum.. thrum" is really the best description of this vibration. It happens every single time when you are in this speed range. Feel like more noticable if your 8-speed tran is in the 8th gear and just cruising. When your hands are on the steering wheel, you definitely feel the vibration and you hear it too. My wife was sitting in the back seat said she did not feel it or heard it. This feels definitely different from the vibrations caused by unbalanced tires (I have had enough of bad experiences on that), in that case the vibration is constant in a speed range, but this vibration comes and goes every second or so, or 1-2 cycles per second. @JimL .


Hope Jeep would have a resolution to this problem.... Should I visit a jeep dealer?? Calling for @JeepCares !

Could this be the drive shaft out of balance? I remember a while ago, I heard something flew out from underneath the jeep and that thing hit the under body, now I am suspecting if it were a balancing weight on the drive shaft??

Also, around 50-55 mph, anyone feel some pressure waves and sounds in the cabin when windows closed and top on? Could it be the same vibration? I thought maybe it was some weird aerodynamic issue, only in that speed range....
You might be on the right track with the drive shaft being out of balance. Or tires need to be balanced on a properly calibrated balancing machine like Hunter Road Force Elite. You would be surprised at how bad some wheels and tires are. Or how much off balancing machines can be off.

https://www.hunter.com/wheel-balancers/road-force-elite
 

JeepCares

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I'm interested to hear of any resolution for the vibration and noise, is this a tire design flaw or tire quality issue? I have 360 miles on my JLU Rubicon and am having the same issue from the first drive home and it's annoying given the sticker for my new jeep was over $55k. I noticed my tires were inflated to 42 lbs PSI and thought reducing to the factory recommended 37 would help. Only made the vibration worse/louder. Starts around 63 mph and up to 67 mph. Seems to be a tire issue that based on this thread is a common issue.

I just traded my 2013 JK Sahara Unlimited after a month in the dealer service and body shop due to an accident and the front drive shaft was dented causing a "similar" noise/harmonic vibration that was resolved with the new driveshaft. This issue started at ~60 mph and dropped off around 67 and then back again at 75+.
Hi Hotlanta,
I understand why this would be concerning. Have you made your dealer aware of this? If so, you may also send us a private message so we can help address and questions or concerns you have.
Lydia
Jeep Social Care Specialist
 

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