Clunk/Rattling noise?

[SSalzer]

I've had a clunking type noise that sounds (I think) like it's coming from the Lt. front somewhere. I recently had my steering box replaced because it was leaking but I don't think that's the cause. I can't figure out where it's coming from. Of coarse the dealership says they can't hear anything and found nothing wrong. I hear it during all different scenarios..... Going over bumps while turning and going straight, while downshifting and releasing the clutch and when I turn the truck off right as the motor shakes violently. I don't think it's my aftermarket exhaust hitting anything. I checked the front end for play... none. I also recently installed a Pacbrake, nothing loose there. A thought I had was possibly a bad motor mount. Has anyone had one fail? Help!

 

[DBentley]

On my 96 the lower front shock bolts would make a similar rattle clunk. They need to be real tite. After market shocks made it worse. Bolts were egg shaped.