My 03 F350 LWB 4x4 made a clattering noise after climbing a high grade hill and dropping back down on the other side. Sounded like it was in the drive train somewhere. It only happened the one time and only after climbing the hill and then going down at idle speed. The road was paved and very smooth. Has anyone had this problem before? I was thinking it may be something with the Turbo but did not really sound like it came from the engine compartment.