Hi, my 2010 Silverado LT 5.3, 6 sp auto has recently developed a buzz that increases in loudness as I accelerate. I can put the transmission in park and slowly rev the engine and it still happens. It lasts for a few minutes and goes away. The truck has 48,000 miles on it now and is just a daily driver. It almost sounds like its coming out of the dash but I am having trouble isolating it because it goes away within 5 minutes. Any help troubleshooting this will be appreciated!