04 mbn C15 has a ticking sound

I just bought this truck and have only put just under 12000 miles on it. As of today its started this ticking sound when under load and with the jake on. It seems to have gotten worse throughout the day. Ive been doing some reading and read that it could be an exhaust leak. I didnt see any soot anywhere tonight. Its a w900 with strait pipes. Ive also read that the valves could need adjusting but they would have to be way out of adjustment to cause a ticking noise. Ive stopped and idled the truck up but a dont hear any ticking noise doing that. Any advise?

 

I looked at the exhaust manifold for broken studs or soot this morning but didnt see anything.

 

The turbo was replaced right before I bought the truck. Definitly going to upgrade the ecm file. Thats the reason I even considered buying an mbn motor. The motor shakes pretty good at high idle (1000 rpm). I dont know if thats mbn related or not. The truck has plenty of power and is averaging 6.1 driving 64-67 mph at 1450 rpm. Of course my last 2 trucks were 12.7 detroits and the one before that had a 355 hp 3406E in it so I definitly havent been in any powerful trucks neither.

 

I bought this truck from a small dealer out in Texas. As far as what the last owner did im not sure. Ive been meaning to have the overhead ran but both shops I use never seem to have the time to get it. Im taking off during christmas break and was going to have it done then.