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Strange vibration - Help Needed

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Old Aug 6, 2016 | 09:01 AM
  #1  
GradyLigon's Avatar
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Joined: Dec 2015
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From: Houston, TX
Exclamation Strange vibration - Help Needed

We just returned home from a long trip from Houston to Yellowstone and back in the Jeep.
Took the Jeep on a couple of great trails in Colorado (Wheeler Lake and Mosquito Pass) and it performed flawlessly other than cracking the rear track bar relocation bracket. (Replaced with a Rubicon Express adjustable track bar the next day).
Had a strange experience and am looking for some help diagnosing what's going on.

On the way home we drove through Dalhart, TX with a lot of construction so slow speeds.
Once we got out of Dalhart and got back up to highway speeds > 60mph there was a lot of noise and vibration in the Jeep, almost like riding on big mud tires but a lower sound.
The vibration was in the body not the steering wheel. I could see the side mirrors visibly shaking but no steering wheel shake like with misaligned tires.
The noise and vibration wasn't really noticeable below 50mph but above that it became progressively louder and more pronounced.
I never got it up above 70 because that was as much as I could tolerate.

We stopped in Amarillo for the night and the next morning I drove over to Discount Tire to have them rotate and balance the wheels, since that's free.
We spun the tires on the lift and didn't really notice anything. With the tires off, nothing was obviously loose or disconnected.

Once they finished I drove through their parking lot a couple times with the windows down listening.
The was a barely audible clicking sound that increased with speed. Road noise drowned it out around 15mph.
No vibration at those speeds.

We drove the rest of the day home to Houston with the same experience, vibration and noise about 50 and nothing below.
Seems to accelerate and shift fine but that vibration and noise is concerning.

Any ideas what might be going on?
My first thought is to check the differentials.

2014 JKU Sahara - 3" Quadratec lift - 315/75/r17 tires
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Old Aug 6, 2016 | 01:04 PM
  #2  
GradyLigon's Avatar
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Joined: Dec 2015
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From: Houston, TX
Exclamation Video from underneath the Jeep

Put my GoPro under the Jeep to see if I could see anything.
Nothing visually obvious but you can definitely hear the sound better.
More concerned now than I was earlier.

Help Please!

Video Here...
https://youtu.be/JytBNcc_D3s
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Old Aug 6, 2016 | 02:25 PM
  #3  
casamtb's Avatar
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From: CLE
Default

Tranny skid plate touching the crossover? Had a similar situation after wheeling. Had bent the crossmember and the oil tranny skid was touching the exhaust crossover pipe. The result was I could feel and hear the vibrations in the floorboard similar to what u described.
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Old Aug 6, 2016 | 04:31 PM
  #4  
GradyLigon's Avatar
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From: Houston, TX
Default On closer inspection...

Looking under my rig again it looks like one of my flange bolts that attaches the driveshaft to the front diff is missing.
Looking closer at the video I can see it there too.

What are the bets that that's the culprit of the noise and vibration?
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Old Aug 6, 2016 | 05:03 PM
  #5  
scubatech's Avatar
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From: Littleton, Colorado
Default

Originally Posted by GradyLigon
Looking under my rig again it looks like one of my flange bolts that attaches the driveshaft to the front diff is missing.
Looking closer at the video I can see it there too.

What are the bets that that's the culprit of the noise and vibration?
They could all be coming loose? Other than that a missing bolt should not cause the vibration.
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Old Aug 6, 2016 | 05:05 PM
  #6  
Biginboca's Avatar
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From: Delray Beach, FL
Default

Originally Posted by GradyLigon
Looking under my rig again it looks like one of my flange bolts that attaches the driveshaft to the front diff is missing.
Looking closer at the video I can see it there too.

What are the bets that that's the culprit of the noise and vibration?
When I read your description I was thinking it sounds like a driveshaft issue right away. It's possible the bolt worked loose due to a seperate issue with your driveshaft, like a missing weight, cv/u joint issue, or even a dent or bend in the shaft itself. Any of those would make the shaft vibrate and then the bolt could have worked loose so don't just think you are free and clear by replacing the bolt.
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