I got at 99 ram 2500 4x4 with a completely rebuilt 12 valve with mods. I blew my phat shaft 66mm turbo and had it rebuilt and machined to an 68mm. I put the turbo back on and ran the truck normal. It ran good all day then out of nowhere I hear a knocking noise and can't figure out what it is. I checked the oil and its good and don't see any leaks. Any ideas???