2008 Sierra 4wd Chirping Noise

[tjthomas77]

I have recently purchased my first ever truck, a 2008 GMC Sierra Z71 CCab, and I love it.

 

However, I notice that when I engage either auto 4wd or 4hi, I hear a faint chirping noise that sounds like it is coming from behind the dash. I also hear this noise when I depress and let off the accelerator while in 4wd. To me it sounds like it may be a computer or a motor that is making this noise when it is trying to detect if it needs to engage the front wheels.

 

Is this noise common with electronic transfer cases?