Rig making new racket today. Ideas?

[wolfman00hd]

In the last day or two, I have been hearing a new noise from what sounds like under the passenger side front of my truck. It is not constant, nor does it have any particular pattern. At first, it sounded to me like a nut had backed off something and something in the suspension was dragging threads back and forth through a hole. I then did some test driving and on a total smooth surface the noise does not exist. Minor bumps or when I push the pedal a little and the engine torques over. Could it be a motor mount cracked or broken? I haven't had a chance to get under the truck and look any further than the upper and lower shock bolts and the sway bar ends. I'd love to identify the prob. before taking it into the dealer. I hate unusual truck noises!!!