weird shudder when driving at certain speeds

DISCLAIMER: I'm aware that the front D30 won't last very long with 37s and I know I should have gone about this build differently. However, it is what it is and I'm going to move forward from here in hopes that I have an extremely capable rig in the future.

My 2014 willys is experiencing a weird shudder while driving.

I have 4.88s, Adam's 1310 driveshafts front and rear, Nitto ridge grappler 37x12.50 17, Mammoth shit wheels, and spidertrax 1.5" spacers.

Right at about 45mph and 65mph, I have this shudder noise. It's nothing I can feel, but I can hear it. It's like driving on the freeway with one window down in some cars. Kinda like a pressure change type shudder. I've moved the tires around, dismounted and rebalanced, and also removed the spacers to see if they might be the culprit. Being that it was speed related, I assumed that it HAD to be the tires.

One of the tires needed about 5.5oz of weights, but that's sitting on the tire carrier at the moment. So, it's safe to assume that it's not the tires causing the problem.

I put the jeep on jack stands and put it in gear to see if anything looked bent or out of whack and all looks well. I'm now at a point where I have no idea what it could be. Hopefully someone has had the same problem and can help out.

Winner gets a bottle of Jameson.

Look for lose plastic body panels. Fender liners, etc. I’ve had stuff like that flap in the wind and make noises like you describe. Not on my Jeep, but other cars.

I checked all that and the noise isn’t coming from something that might be loose. It’s an audible vibration. I wish I could explain it better.

You have a tramp stamp on the back? If you have the rear gate rubber fins blocked off, this will create a pressure difference in the cab that you are describing.[emoji848] its a guess...
I need a shot of Jameson about now


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I have a Smittybilt HD tire carrier.

I wonder if the tire carrier is blocking them. I’ll have to check that out.

If this is the problem, are you sure you want just a shot? I’m talking about bottles!!

So, I took the tire carrier off and saw that the tailgate vent was slightly blocked. It's also falling apart so I completely removed it. I left the tire carrier off and I went for a drive to find no change in the problem. I reseated the top and freedom panels, retorqued all bolts to factory spec and still no change. I had my wife sit in the driver seat while I pounded on the top from the outside and she said it sounded exactly like what we hear when driving.

I saw somewhere that people were shoving towels between the sport cage and the top to act as a buffer to keep the top from fluttering or "buffeting".


If that doesn't fix it, I'm going with a soft top and will need recommendations.

Do you have a light bar or other accessory that could be causing wind cavitation?

Do you have a soft top? You have swapped out your driveshaft, check your bolts too to be sure, I have something I thought was wheel/tire and was a loose bolt on the driveshaft.

fiend said:

Do you have a light bar or other accessory that could be causing wind cavitation?

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I do not. I have a-pillar lights, but the problem was there prior to the lights.

rl206 said:

Do you have a soft top? You have swapped out your driveshaft, check your bolts too to be sure, I have something I thought was wheel/tire and was a loose bolt on the driveshaft.

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Hard top.

For what it’s worth, the problem was apparent even prior to the driveshaft install.

Lift, flat fenders, gears, rear locker were installed prior to the problem starting.

There are no apparent driveline vibrations that would cause this.

Also, the shudder/noise is louder when I hit bumps on the freeway.

I tried the towel trick and the heavy shudder stopped. However, I now realize I have a vibration somewhere in the rear end. lol

Hood flutter?


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JKJKJKJLJL said:

Hood flutter?


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Click to expand...

I already have a hood lock and better latches, so that's out of the question.