Hey, My buddy is looking at an 06 mega 4x4 2500 52,000 miles. It's got Nav but I does not work, its asking for the disc and when you put it in it does not recognize the disc. Also the oil is over full by 2 inches and the automatic transmission fluid is not real red its a little brown. I know that this does not sound all the good but what big problems are these things related to??