2011 Silverado front end clunk/pop

[Denali09Sierra]

Hey Everyone, 

 

Haven't been on here since I sold my 09 Denali, please forgive me as I have gone back to a Dodge Ram - strictly for the Cummins.  Love it btw. 

 

Anyways, my wife recently got an 2011 Silverado 1500. It's developed a serious front end clunk/pop while turning left. She just brought this to my attention, and I went out to take it for a test ride. Sure enough, lots of clunks, look down - and the 4x4 is on! Yikes. My brother in law is a GM honk and confirmed these trucks don't have a light that pops up on the dash - kinda dumb, huh? 

 

Anyways, a quick Google search showed there was a big problem with ISS with GM trucks for a long stretch of time. Was this still an issue with 2011 pick-ups? Wondering what I should be looking for when I check for damaged/worn parts this Sunday (my day "off"). I'm not familiar with IFS systems as I've always had a solid front axle in my trucks. TIA.