2000 tahoe 4wd with humming / buzzing

[mike tahoe]

I have a 2000 tahoe 4wd with a humming / buzzing sound coming from
underneath the bottom of the truck on the drivers side. Anyone experience this problem? Cant seem to pin it down.

 

[Rivieraracing]

When do you hear this noise normally, while driving? Idling? Braking? Turning? Coasting down the road straight or turning? Let us know, this will help alot with diagnosing the problem.

 

[mike tahoe]

Most noticable during idle, but is present most all the time. I was thinking
it was a heat shield or something vibrating, but it does not seem to change frequency or volume at higher RPMs..