Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
Welcome, I'm Chris (aka Moose).
I am sorry so far all other techs have passed on this question. I am on vacation not working as many hours as normal. I will try to help when I can if help is still needed.
Can you duplicate this noise in park just reving the engine?
Is it related to the AC being on or the HVAC blower being on?
Hold the rpms up in park so the noise occurs. Does the noise change as you change the blower speed. If so then I recommend a new ground added to the blower motor resistor as a first attempt.
Now that I have posted a partial or complete answer, you will see you can rate me. The deposit you have already paid is not transferred to me until you rate me. I would like to receive nothing less than 5 star excellent ratings. So if we are not there yet, please reply and let me help more. If you're not pleased, let me know because rating bad does not result in a refund, there are better options. Rating now will not close this post nor prevent replying. Thanks Chris