U can only hear this particular noise inside of truck not under hood


https://youtu.be/mvwnsh8wJ7M

 

First thing that came to mind is interference from the engine to the speakers.
Some vehicles come with a wired in resistor to clean the power up from the battery.

Years ago in my dads 97 c1500 he put in an old style hands free with the corded mic and speaker that plugged into the cig lighter. As he drove, the speaker unit made that high pitched whirring noise and it got louder with revs. It was the injector pulses that were being picked up. Just my 2 pennies.

 

Does it cut in and out or change with rpm?

 

Yes it changes with rpm. And if i change the load on it. It quiets are gets louder. My 1st thought was tourque converter bolts lose. But its top of the motor or bell housing area. And for some reason my valves are starting to chatter more any thoughts?

 

So your for sure its not coming from the speakers I guess?

 

Pretty sure. Its like right in front of radio. But a knocking sound so weird knoe 1 can really pin point it. 3 shops iv taken it to.

 

Blend door slapping? Just a thought can you get a better video

 

I thought the same thing but he said that it changes with RPM.... hmmm idk

 

Do you have a stethoscope? If not you can use a clean extension. Put it on the engine and in your ear. Keep moving it around the engine until you find it. Sounds funny but it works.

 

Also maybe disconnect the serpentine belt to confirm that it isn't any of your accessories making noises.