Larry, welcome to the forum!!
Sorry to hear of the issues you are experiencing with your new MH. It seems like quite a few members are having problems also.
One thing to think about on the crack in the back cap is--could it possibly end up causing water intrusion to the coach. That is something I would want taken care of ASAP. If you can't get satisfactory service from your dealer, you might consider contacting Thor directly. Seems as tho people some times get better results that way.