Diesel knocking

Hi I was going to school the other day when something blew on my truck and it knocks very badly now. There isn't any oil leaking and the oil pressure is fine. The truck still start,s but it knocks badly. I've only started it once since it happened, my tuner threw a code, but I didn't read all of it before I cleared it, it said something crankshaft that was a new engine in it with 12,000 miles on it and h&s custom tune it's a 2008 lmm duramax with 220 hp tune stage 3 motor stage 3 transmission 76mm turbo 90hp injectors.