Alittle help figuring out engine noise!

[Butzdiesel]

Heres the deal, engine is chattering like hell at acceleration and when holding at steady throttle. It fades away when at wot but as soon as the rpms level out it starts again. Turned my tst off and still black smokes and is still noisey. I have no codes and the truck runs fine-no power loss or nothin. What do you guys think? Timing? Railpressure? Pulled the valve cover off and everthing seems to be ok in there.