2006 gmc sierra drivers side front end whistling

[vjjack04]

Guys, I have an 06 gmc Sierra that has alway had a little brake squeak since I last changed the brakes, but now it has started making a whistling noise when i drive it...only happens when rolling. A couple years ago I changed the pass side half shaft (it's 4 wheel drive), but did not change the drivers side. The rotors seem to look ok with still good brake pads....I was wondering if the half shaft could be the problem, maybe it's begining to go and causing some play in the area....but its odd because this is not a squeaking sound, it's a definent whistle....any ideas?