05 Chevy suburban ticking under the dash

[Itsmysuburban]

I have a ticking behind my dash. It is speed dependent. I can start to hear it around 25 mph and then at 65 it is moving fastest enough that you can not hear it. There is no big thuds going over pumps or throwing it into a high speed corner.  I also turned hard corner to check the cv joints and nothing. I pulled the dash and fuses for HVAC cruse control but nothing changes the sound. I can not hear the sound outside. None of my gauges are acting weird and the stepper motets where replaced last summer. 

[Jsdirt]

You could be hearing an exhaust leak from the one, or both of the donut gaskets at one or both the manifold flanges. It would be engine speed related, but not vehicle speed related, however.

 

Or, you've got some broken plastic pieces for the blend door drive motors in your HVAC system. Sometimes they will constantly try to move to the home position, resulting in an annoying click. I had a '11 Impala here many years back that did this constantly, even key out and locked! What a POS that thing was ... but I digress.

[Itsmysuburban]

53 minutes ago, Jsdirt said:

You could be hearing an exhaust leak from the one, or both of the donut gaskets at one or both the manifold flanges. It would be engine speed related, but not vehicle speed related, however.

 

Or, you've got some broken plastic pieces for the blend door drive motors in your HVAC system. Sometimes they will constantly try to move to the home position, resulting in an annoying click. I had a '11 Impala here many years back that did this constantly, even key out and locked! What a POS that thing was ... but I digress.

Thank you. It is definitely tied to speed of the car. I have taken it out of gear while traveling and reved the engine and sound did not change. I also pulled the fuses on the HVAC and the sound still happened which I am assuming would quiet the blend door motors.  

[Jsdirt]

Yeah, you're right about the blend door motors ... and while typing that one, I forgot you had mentioned it was speed related! 

 

Only other thing I can suggest is to check the driveshaft. Could be something hanging and bouncing off it occasionally, or, you have a failing universal joint.

 

You've got an interesting one there! Let us know what you find out in the future.

 

Sorry I couldn't be of more help. Internet diagnosis is borderline impossible.

[davester]

You could try lifting the front wheels up and spinning them manually to see if you can hear anything.  And if you have 4wd and enough jackstands, you could perhaps try getting all 4 wheels off the ground, putting it in 4wd, getting the wheels up to speed and then seeing if you can narrow down where the sound is coming from.

[Jsdirt]

Yeah, that's another good idea - could be a rusty or bent dust shield hitting the inside of the hub, or brake rotor.

[Itsmysuburban]

11 hours ago, Jsdirt said:

Yeah, that's another good idea - could be a rusty or bent dust shield hitting the inside of the hub, or brake rotor.

I did check all of the u joints and dust shield on the front

[Itsmysuburban]

12 hours ago, davester said:

You could try lifting the front wheels up and spinning them manually to see if you can hear anything.  And if you have 4wd and enough jackstands, you could perhaps try getting all 4 wheels off the ground, putting it in 4wd, getting the wheels up to speed and then seeing if you can narrow down where the sound is coming from.

I did pull the front left tire to check the hub. I spun the wheel as fast as I could but with 4wd there was to much drag to get it really going. I do not have enough jack stand or guts to get it up to speed while up on jack stands. My drive is pretty step

[tlaw91]

So can you take a video and post it with the noise? Preferably on YouTube.
Otherwise we ain’t gonna be much help


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[Itsmysuburban]

On 5/25/2020 at 3:18 PM, tlaw91 said:

So can you take a video and post it with the noise? Preferably on YouTube.
Otherwise we ain’t gonna be much help


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I upload it to You tube at 

 

audio only of my suburban.m4a

[Itsmysuburban]

I hope this will help

[Jsdirt]

That sure sounds like something rubbing on the driveshaft to me. Either that or a failed U-joint.

[tlaw91]

Yep I agree something with the driveshaft. Rotates only with speed. Would need to have on lift and run it in the air with someone underneath to find it


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[Itsmysuburban]

On 6/3/2020 at 6:00 PM, Jsdirt said:

That sure sounds like something rubbing on the driveshaft to me. Either that or a failed U-joint.

It was a u-joint on the front drive shaft

[Itsmysuburban]

Thanks everyone