Clunk noise on the front end

[JMVH2]

About 2 weeks ago I started to heard a clunk noise on the front end of my truck, it only makes it when it has been parked for a while; when start moving forward and you turn the wheel you hear a "CLUNK" noise from the front end then you can drive it all day and will not make it until it has been parked for a while. I took it to the dealer 3 days ago (2.5 hours away) spent all day there and they told me that the front skid plate was loose and that was the problem! well the noise came back the next day, I called them and as usual they told me to bring it back. Do any of you have any idea what could be? May be is something I can check my self instead of taking it all day there for them to do nothing! Thanks