Uggg. I hate to tell you this but I believe that you may have had the dreaded Conecting Rod problem that seems to be more and more common with the newer Machs. I honestly wouldn't pull the engine apart any farther. Just remove it and send it back to Horizon. They seem to have been pretty good about fixing them for no cost to those that have had problems. Good luck and don't give up. It's a great truck. I have 3!