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Discussion Starter #1
When i'm driving sometimes i get this sound.

We intially thought it was wheel bearings but my mechanic says it's not.

Anyone have any idea what this is?


Also how to i attach or link to a sound file?
 

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Discussion Starter #3
I wish, if i could link the audio you'd understand it can completely drown out the audio with the sound.
 

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Throw a quick vid up on youtube with audio capturing the noise then provide the link here....
 

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Discussion Starter #6
Light bar yes, but the light bar has a different sound. This can happen at 1-5 mph and continues to happen up past 70 most light bar sounds are over 40mph.

I'm working on encoding the audio file to a video.
 

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you would be correct in that assessment.....but I did recommend posting up a youtube link. You're welcome.
 

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Sounds like the light bar whistling. Pull it off and take it for a spin.

Sent from my SM-N910V using Tapatalk
 

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Discussion Starter #12
It's not the light bar.It can happen at 1 mph and it doesn't happen when i'm not moving this is something in the drive train.

Also the longer you drive the louder it gets. It eventually will completely over power the radio.
 

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Discussion Starter #14
You state I tis related to drivetrain, is it related to vehicle speed which I suspect not. Or related to engine speed or load?
It's not related to engine speed or gear, it happens at any speed. Including 1 mph which wouldn't be the light bar. As speed increases sound pitch changes. Listen to the audio later in the clip you can hear it all the way to stopping.
 

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as weather cools the belt will contract with the temps. You'r idler pulley or one of the other belt driven things is squealing cause it has a bad or muddy bearing or pulley bushing it sounds like, to me. As you accellerate the engine leans back ever so slightly increasing the tonal squeal by a tiny amount but enough to raise the pitch.

I would have my wife drive down the road with me on the hood with a crash helmet on but I do not advise you do that; put a go pro or other camera up near front and see if it isn't emitting from the space between the fan and the pulley. Looks like you've been going thru some wet gravel which is great for that or the drive shaft /pinion to get coated in that abrasive crap.

:jeep2:


 

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as weather cools the belt will contract with the temps. You'r idler pulley or one of the other belt driven things is squealing cause it has a bad or muddy bearing or pulley bushing it sounds like, to me. As you accellerate the engine leans back ever so slightly increasing the tonal squeal by a tiny amount but enough to raise the pitch.

I would have my wife drive down the road with me on the hood with a crash helmet on but I do not advise you do that; put a go pro or other camera up near front and see if it isn't emitting from the space between the fan and the pulley. Looks like you've been going thru some wet gravel which is great for that or the drive shaft /pinion to get coated in that abrasive crap.

:jeep2:

That is why I asked about engine load. I listened to the video and it sounds like an idler pulley.
When ford did away with the distributor on and 4.0 and 3.0 motors they installed a cam shaft synchronizer in its place rear top end of the motor. Some engineer had the great idea that splash lubrication at the rear top end of the motor was a good idea, well the part fails very often from lack of lubrication and it makes the sound exactly like that. I am not aware of such a part on the 3.8 or 3.6l. so this does not help him but I will say the sound of a failing cam synchro on the 4.0 is completely random sometimes loud others not so loud and you have to get the hood open while it is doing it to track it down.
 

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Discussion Starter #18
as weather cools the belt will contract with the temps. You'r idler pulley or one of the other belt driven things is squealing cause it has a bad or muddy bearing or pulley bushing it sounds like, to me. As you accellerate the engine leans back ever so slightly increasing the tonal squeal by a tiny amount but enough to raise the pitch.

I would have my wife drive down the road with me on the hood with a crash helmet on but I do not advise you do that; put a go pro or other camera up near front and see if it isn't emitting from the space between the fan and the pulley. Looks like you've been going thru some wet gravel which is great for that or the drive shaft /pinion to get coated in that abrasive crap.

:jeep2:


That is why I asked about engine load. I listened to the video and it sounds like an idler pulley.
When ford did away with the distributor on and 4.0 and 3.0 motors they installed a cam shaft synchronizer in its place rear top end of the motor. Some engineer had the great idea that splash lubrication at the rear top end of the motor was a good idea, well the part fails very often from lack of lubrication and it makes the sound exactly like that. I am not aware of such a part on the 3.8 or 3.6l. so this does not help him but I will say the sound of a failing cam synchro on the 4.0 is completely random sometimes loud others not so loud and you have to get the hood open while it is doing it to track it down.

Yet the pitch/tone doesn't change with engine speed. Just wheel speed. This isn't something on the engine.
If i bring the engine to idle at 70mph it doesn't change the sound. Only slowing down changes the sound. This is NOT engine/transmission related as RPM does not effect the sound in any way.
 

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have you taken a pressure wash or better than average garden hose and sprayed the rad and fan clean from inside the engine bay ?
Be careful of holes if OEM but from your adamant and certain assured ness that it has nada to do with any engine related spinning there are only the unitbearing , dustshield -caliper and /or the fan left that could be the culprits.

With someone else driving it in circles around you in a parking lot or while you are in traffic free zone and in pssgr seat hanging out a little you can isolate the general area sounds emit from easily.

You have gravel juice or gritty mud someplace in one of those three . The only other thing could be MAYBE if you’ve gotten said grit mud on axle seals up front ...
Be careful if you do hang out of pssgr seat to isolate it


:jeep2:

 
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