When I take off in my 2011 Silverado, I hear a clunk in the front. It will make the noise only once and only when it sits for a while and only going forward. Example, I back out to the road, go forward and there is the noise. I will go to the store, come out, start up and leave. It will make the noise when I take off. I don't think it is in the steering. It is not a metallic hit, more like a dull clunk. Any ideas?