24 Dark Horse high frequency highway vibration

[Shneakyman]

Hello all, purchased my 2024 mustang dark horse a few months ago and recently within the past 2-3k miles it has had a pretty noticable high frequency vibration starting at 60-65mph and getting worse as speed increases. Feel it more in the chassis of the car( floor, doors, console, roof) not much in the steering wheel. Pressing the brakes doesn't change it and can put the car in neutral without any change. The vibration is also accompanied by a low rumbling/hum noise, almost like bass feedback. Dealership has had it twice for almost a month. They have "rebuilt" the rear diff, replaced the driveshaft, and balanced and replaced tires. Nothing has helped the vibration and I have been told that's just how Mustangs are.

I'm pretty confident that it is in the drive line but haven't seen many that have successfully fixed an issue similar to this. A few filed lemon law but I have seen one that they replaced "the back whole axle" and that's all the info they gave. Wasn't sure if anyone has experienced this or knows anyone who has. Just trying to help point Ford in the right direction. Thanks! Oh and car has 29k miles, non HP, and stock other than an X-pipe.

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[Sofa King]

Could be a wheel bearing... do a couple of quick side to side turns and see if there is more noise to one side or the other.

 

[Shneakyman]

Could be a wheel bearing... do a couple of quick side to side turns and see if there is more noise to one side or the other.

Doesn't change side to side. And the dealer checked all 4 and said they were good.

 

[MAT1955]

@Shneakyman ..... so you have an X pipe. Did your DH come with this? X pipes are known to have "special effects" aka rumble, vibration, etc. at certain rpm/mph ranges. H pipes don't seem to be prone to the "special effects" afflictions of X pipes. Do you know the history of your DH? Was it ever in an accident? Have you had a 4 wheel alignment which should rule in or out frame damage - even very minor frame damage or suspension damage from an accident can cause vibrations/noises at different speeds.

 

[Shneakyman]

@Shneakyman ..... so you have an X pipe. Did your DH come with this? X pipes are known to have "special effects" aka rumble, vibration, etc. at certain rpm/mph ranges. H pipes don't seem to be prone to the "special effects" afflictions of X pipes. Do you know the history of your DH? Was it ever in an accident? Have you had a 4 wheel alignment which should rule in or out frame damage - even very minor frame damage or suspension damage from an accident can cause vibrations/noises at different speeds.

It came with the x pipe, and putting the car in neutral doesn't change the vibration which should rule that out. The car has a clean car fax and has had two alignments since I have owned it. None of which showed any issues in that regard.

 

[Grumpywizards]

You're right up there on milage where I would do a transmission fluid change so ask them to just drop the pan and take a look inside. Mine did it and it turned out to be the part that the half shaft pushes into the differential, the gasket had torn so it became metal on metal. You have to pry them off so its not a normal thing people just replace. I'll link it.
https://share.google/sIdQf7AIRfn1KVMhU

 

[MAT1955]

@Shneakyman ..... good news on the alignments. Putting the car in neutral is not the same as driving it at highway speeds. I have heard a number of owners say X pipes caused noise and vibrations. I do like @Grumpywizards suggestion!

 

[Shneakyman]

You're right up there on milage where I would do a transmission fluid change so ask them to just drop the pan and take a look inside. Mine did it and it turned out to be the part that the half shaft pushes into the differential, the gasket had torn so it became metal on metal. You have to pry them off so its not a normal thing people just replace. I'll link it.
https://share.google/sIdQf7AIRfn1KVMhU

That's on my radar but the dealership wants $1300. As a technician (not Ford) I can just do it myself when I get some free time. And they just rebuilt the rear diff and didn't mention anything about half shaft issues. I'll ask them about it though, thanks!

 

[Shneakyman]

@Shneakyman ..... good news on the alignments. Putting the car in neutral is not the same as driving it at highway speeds. I have heard a number of owners say X pipes caused noise and vibrations. I do like @Grumpywizards suggestion!

I apologize for not being specific, it is put in neutral while driving not just sitting still. So it is still at highway speed when in neutral and the vibration doesn't change.

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