My ipod classic (160gb) appears on the desktop in Finder, but does not appear in iTunes. HELP!

My ipod classic (160gb) appears on the desktop in Finder, but does not appear in iTunes. I have tried resetting the ipod, using different cords, uninstalling/reinstalling iTunes, and putting the ipod into disk mode. Other than this problem my ipod works perfectly, it plays all my music, doesn't freeze or anything, I just can't get it to show up in iTunes. Any ideas? I don't want to have to lose all my music, because I'm not sure I have it all backed up. But even so, I can't get it into iTunes to wipe it anyways. It's been a couple months and I am out of ideas!