I have noticed that the last week, when I go to work in the morning, my 2011 GC Lerado 4x4 sounds like it has a hole in the exhaust and my front end clunks when going down the road. I noticed after it warms up the hole in the exhaust noise goes away and the clunking from the front end fades away. I have 32,500 miles on it and I doubt it's the ball joints, U-joints or the front drive line & it's U-joints. The 32,500 is all highway miles and no off roading. Has anybody else had this issue?