PLEASE HELP!!! I can NOT figure out what this noise is...

[Austinite]

After seeing your underhood pics, that's gonna be the hardest noise ever to pinpoint. You need to take your hood off, give one of your homies a couple of Miller Lites, and strap his ass on the front with a GoPro and an external microphone and cruise down a backroad a few times then review the footage.

 

[Rocket Man]

Also to everyone suggesting the alt,

The noise only happens while I'm in drive and going down the road, there is no noise if I rev it up in park or neutral, only while going down the road.

And the noise will go away, even if I'm still going 40+ down the road as long as I'm not pressing on the pedal.

If it was my alt, wouldn't the noise be present anytime my rpms increased, weather or not I'm actually moving down the road???

It's hard to say; might be just when the engine is under load. Either way it needs to be eliminated so you can look at other possibilities. I've always learned to eliminate the most likely causes one by one until you're left with the least likely ones because they're the hardest to find. I've had my ass kicked because I assumed it couldn't be one thing (nah, it couldn't be that), only to find out it was after chasing everything else until I was blue in the face.

 

[KJMac1071]

Does it make the noise if you powerbrake it? I would load it up in drive, might be a torque converter or pump! My friends 4L60 did that in his trans am. It sounds like ps pump, have you check fluid level?

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[retiredsparky]

Fuzzy,
I can understand why so many posters have focused on the alternator, because the noise is a kind of classic sounding electrical high pitched sound.

However, I suggest that there are other possibilities (I am certainly not ruling out the alt, by the way): could it be a shaft in the drive system ( tranny, drive line, wheel bearing, etc) or the engine/belt driven accessories that has brinnelling. There are several different sounds that worn bearings can make, and I think it is possible that a shaft or a set of worn bearings could make this noise. The noise can be made by very slight, but repetitive imperfections. A water pump, even if gear driven, power steering pump, alternator, a/c compressor and its clutch assembly could produce such a noise.

A transmission that was rebuilt, but had a shaft with a worn surface or a set of bearings that were not replaced, because they looked ok could cause this noise. U-joint needle bearings are also a possibility.

Another possibility is that high amperage surges caused by the alternator/sound system have caused damage to a set of bearings on the truck, which then can create strange noises.

Another unlikely possibility is that at some time tires with a silicon rubber composition (provides longer life)were used on this vehicle, which can generate higher levels of static electricity thereby damaging the wheel bearings (this type of bearing damage has been documented over the years), resulting in the strange noise. There have been many cases of toll operators who have been shocked by static electricity when collecting tolls from drivers of vehicles with silicon compounds in their long life tires. In a previous life, I sometimes replaced electric motor bearings damaged by high levels of static D.C. electrical voltage. The bearing noises sounded a lot like your vehicle. Again, this is a long shot--but my point is that there are many possibilities here.

One last point: bearing clearances can vary by temperature, so it is conceivable that ambient air, lubricant or vehicle temperature or load on the component could change/eliminate the noise. We wish you the best of luck!

Your idea of using the microphone system is a good one.
Larry

 

[bottomline2000]

Air filter service gauge, aka filter minder?

This!! Plug that hole rather than tape it off and see if it goes away. That would explain the sound going away when off throttle, it sounds like it's creating a harmonic. It's basically a big vacuum leak and whistling under load. Your computer is not gonna freak out because it's pre maf sensor..

To test that throw the truck in neutral while its making the sound and let off the gas immediately and the sound should just stop since the throttle body is closing. You still have that big factory tube so it's smoothing out the air going into the intake which is exactly what the sounds is mimicking.

Be wary of any idiots on the road behind you before doing this lol.

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[iamdub]

He posted the busted filter life monitor on 2/11 and hasn't reported back yet if it made any difference. Maybe he hasn't driven it since? With such a problem, I would've hopped in and taken it for a spin immediately after taping up the hole.

 

[xFuZzYx]

Fuzzy,
I can understand why so many posters have focused on the alternator, because the noise is a kind of classic sounding electrical high pitched sound.

However, I suggest that there are other possibilities (I am certainly not ruling out the alt, by the way): could it be a shaft in the drive system ( tranny, drive line, wheel bearing, etc) or the engine/belt driven accessories that has brinnelling. There are several different sounds that worn bearings can make, and I think it is possible that a shaft or a set of worn bearings could make this noise. The noise can be made by very slight, but repetitive imperfections. A water pump, even if gear driven, power steering pump, alternator, a/c compressor and its clutch assembly could produce such a noise.

A transmission that was rebuilt, but had a shaft with a worn surface or a set of bearings that were not replaced, because they looked ok could cause this noise. U-joint needle bearings are also a possibility.

Another possibility is that high amperage surges caused by the alternator/sound system have caused damage to a set of bearings on the truck, which then can create strange noises.

Another unlikely possibility is that at some time tires with a silicon rubber composition (provides longer life)were used on this vehicle, which can generate higher levels of static electricity thereby damaging the wheel bearings (this type of bearing damage has been documented over the years), resulting in the strange noise. There have been many cases of toll operators who have been shocked by static electricity when collecting tolls from drivers of vehicles with silicon compounds in their long life tires. In a previous life, I sometimes replaced electric motor bearings damaged by high levels of static D.C. electrical voltage. The bearing noises sounded a lot like your vehicle. Again, this is a long shot--but my point is that there are many possibilities here.

One last point: bearing clearances can vary by temperature, so it is conceivable that ambient air, lubricant or vehicle temperature or load on the component could change/eliminate the noise. We wish you the best of luck!

Your idea of using the microphone system is a good one.
Larry

Thank you for all of the suggestions, I will go through these and see if I can figure anything out.

 

[xFuZzYx]

This!! Plug that hole rather than tape it off and see if it goes away. That would explain the sound going away when off throttle, it sounds like it's creating a harmonic. It's basically a big vacuum leak and whistling under load. Your computer is not gonna freak out because it's pre maf sensor..

To test that throw the truck in neutral while its making the sound and let off the gas immediately and the sound should just stop since the throttle body is closing. You still have that big factory tube so it's smoothing out the air going into the intake which is exactly what the sounds is mimicking.

Be wary of any idiots on the road behind you before doing this lol.

Sent from my SAMSUNG-SM-T377A using Tapatalk

He posted the busted filter life monitor on 2/11 and hasn't reported back yet if it made any difference. Maybe he hasn't driven it since? With such a problem, I would've hopped in and taken it for a spin immediately after taping up the hole.

So yeah, right after taping that up, me and my friend/mechanic went to take a ride to see if that fixed it, but we could still hear it, I just never updated that specific possibility, my bad.

But my truck was riding extremely rough so my mechanic looked into my front suspension and noticed my tire rods on both sides were completely shot, to the point that on the drivers side the boot that covers up the ball joint on the inner tire rod side was missing and the ball joint would pop out and back in when hitting big bumps in the road... I went and got 2 HD Moog inner and 2 HD Moog outer tire rods and completely replaced them on both sides.
We also noticed my sway bar bushings and pitman and idler arms were completely shot. Those last 2 items are why my truck would bounce while turning. So I'm currently saving up to buy the HD Moog pitman and idler arms so I can have my friend replace those also and hopefully my front end will have everything replaced that I need to replace so I can get it aligned again and get back to figuring out this noise.
I might have to wait until I get my taxes to get back to this specific problem but honestly what else do you expect at 252k miles with 6" lift and 22x14's wrapped with 35x12.50 M/T's lol.

Lastly, does anyone here think that my tire rods or Pitman and idler arms could have been responsible for that noise?

 

[Rocket Man]

So yeah, right after taping that up, me and my friend/mechanic went to take a ride to see if that fixed it, but we could still hear it, I just never updated that specific possibility, my bad.

But my truck was riding extremely rough so my mechanic looked into my front suspension and noticed my tire rods on both sides were completely shot, to the point that on the drivers side the boot that covers up the ball joint on the inner tire rod side was missing and the ball joint would pop out and back in when hitting big bumps in the road... I went and got 2 HD Moog inner and 2 HD Moog outer tire rods and completely replaced them on both sides.
We also noticed my sway bar bushings and pitman and idler arms were completely shot. Those last 2 items are why my truck would bounce while turning. So I'm currently saving up to buy the HD Moog pitman and idler arms so I can have my friend replace those also and hopefully my front end will have everything replaced that I need to replace so I can get it aligned again and get back to figuring out this noise.
I might have to wait until I get my taxes to get back to this specific problem but honestly what else do you expect at 252k miles with 6" lift and 22x14's wrapped with 35x12.50 M/T's lol.

Lastly, does anyone here think that my tire rods or Pitman and idler arms could have been responsible for that noise?

I have heard from others that have tried to install the Moog pitman arm that it won't press on all the way on our trucks. Several people have reported this. I went with the AC Delco Professional for that part and Moog with everything else. As far as the noise, I don't see how any of those parts could cause it.

 

[xFuZzYx]

I have heard from others that have tried to install the Moog pitman arm that it won't press on all the way on our trucks. Several people have reported this. I went with the AC Delco Professional for that part and Moog with everything else. As far as the noise, I don't see how any of those parts could cause it.

I didn't think those parts could/would be responsible for it either, but I just figured what could it hurt to ask? Figured y'all would know more about whats going on mechanically here than I do lol.

 

[bottomline2000]

I didn't think those parts could/would be responsible for it either, but I just figured what could it hurt to ask? Figured y'all would know more about whats going on mechanically here than I do lol.

Hard to tell without looking at my truck but does that filter life monitor allow air into MAF without going thru the air filter? U may have dirt on the MAF sensor..and I would plug that hole, not just tape it up. Technically it can still suck air thru the hole and I doubt the tape would stop it.. I wouldn't rule it out unless something were plugging the hole completely. An old spark plug or something just to test.

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[iamdub]

So yeah, right after taping that up, me and my friend/mechanic went to take a ride to see if that fixed it, but we could still hear it, I just never updated that specific possibility, my bad.

Well, shit.

Lastly, does anyone here think that my tire rods or Pitman and idler arms could have been responsible for that noise?

No way at all.

 

[xFuZzYx]

So a bit unrelated, but check out what I picked up yesterday...

Here's a before install pic:

And here are 2 after install pics:

I can not believe how much cleaner my Tahoe looks under the hood now with the new filter.

 

[Tonyrodz]

So a bit unrelated, but check out what I picked up yesterday...

View attachment 193125

Here's a before install pic:

View attachment 193126

And here are 2 after install pics:

View attachment 193128
View attachment 193129

I can not believe how much cleaner my Tahoe looks under the hood now with the new filter.

Not cleaner, sexier.

 

[Rocket Man]

Yeah that stock tube is ridiculous.

 

[bottomline2000]

Do you still have the sound? If you get rid of that clutch fan it will be even cleaner.

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[xFuZzYx]

Do you still have the sound? If you get rid of that clutch fan it will be even cleaner.

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I haven't really gotten a chance to drive it much since swapping it out, the noise doesn't happen much, or if it does happen it's not very loud, when driving around town, the main time you notice it is while going down the highway, which I haven't had a chance to drive my truck on the highway since changing out the filter, but I will update y'all tomorrow on if it's still there and if it is, if it has changed any after the swap.

 

[xFuZzYx]

UPDATE:

I removed my High output alternator and sold it to a friend so I'm currently running a stock alternator while I wait on my new one to get here.

And the damn noise is still there.

Also I replaced my tire rods, my pitman arm, my idler arm, and my sway arm bushings in my front suspension and my truck rides like a brand new truck again..

 

[DenaliBQ]

i have the same noise on two yukons 2002 and a 2003 only does it when its below 40 degrees or so and under same conditions as you

 

[xFuZzYx]

i have the same noise on two yukons 2002 and a 2003 only does it when its below 40 degrees or so and under same conditions as you

Any idea as to what it is?