Why does my 360 get abnormaly when I play GH3?

when I put my GH3 disc it starts to make a really loud noise that goes from the normal mmmmmmmmmmm to rrrrrrrrrrrrrrrrr is that bad or is it supposed to that?

Try using another 360 game and see if it does the same thing. "mmmm to rrrrr" really doesn't explain whats happening to your xbox. To me that seems normal because most games when they start up spin slow for a few seconds, then speed up.. which makes a similar sound to "mmmm...RRRR".