beezermascu

Called dealer today, rear differential will be done by Monday. They are already ordering more rear differentials based or corporate engineering claiming this will fix issue. Supposedly slippage is causing electrical feedback as the system attempts to engage and adjust. Will advise on Monday. Sent from my iPhone using Tapatalk

Ok, there may be some forward progress here!! My hometown dealer has had a few customers bring in their trucks complaining of this issue. Apparently this dealer has staff with better hearing than most. Anyways, it merited a visit from gm engineering and they have said it is electrical feedback from the rear differential having too much backlash (slack between gear teeth apparently). Each dealer is equipped with a dial indicator and can test the backlash. The engineer advised a rear differential replacement. Too early to tell whether this will ultimately fix the issue, but we shall find out soon once it is replaced. I will post any results as I have them Sent from my iPhone using Tapatalk

I switched from auto to 2wd and it is gone!! Back to 4wd high, lo, or auto and the sound is back. Deferring to this post as it seems to be a common problem. http://www.gm-trucks.com/forums/topic/155509-high-frequency-noise-coming-from-dash-when-in-4wd/ Sent from my iPhone using Tapatalk

Just purchased a brand new Denali four days ago and as soon as I put the car in gear (forward or reverse) I hear a very high pitch electrical chirp from driver's side dash speaker. It seems to be primarily present when applying gas once driving. If I start the car and never put it into gear, none of this high pitch feedback is present once I shut it off. However, if I start the car and stay in place with the brakes applied, then shut the car off, there is a lot of this chirping. The chirping can be heard even with the stereo is very loud. Very frustrated having paid so much money and the chirp is very annoying. Thinking this may be a side effect of a malfunctioning Active Noise Cancellation system, but overall fearful it will be hard to diagnose. All cell phones have been shut off and noise is still present so it is not electrical interference with cell phones. Have an appointment with the local dealership in a week and a half. Appreciate any help!! Sent from my iPhone using Tapatalk