Front diff /front end noise!!!

[GSHOCK]

Snapping, slapping, popping noise coming from front end / diff of my 2005 H2 w/ 37k miles when turning left out of parking spaces / driveways. Initially thought it was coming from suspension, but after a trip to local suspension shop they said it was coming from diff. Had fluids changed recently and thought maybe a non synthetic oil was used, so drained diff and put in Royal Purple and even added GM limited slip additive for extra lube. Noise still there! It sounds almost like plastic snapping! Maybe new half shaft needed, diff gears slipping! I'm not sure where to start, but I don't want to start tearing my truck apart w/o some sort of direction! Any ideas?!?