Syncing iPod Classic with iTunes???

Does any know how to transfer/sync all my music off my old iPod Classic to my iTues app on my new computer.

I thought when I did this before a long time ago it automatically synced up together once I connected my iPod Classic to my computer and opened the iTunes app.

I have over 9,000 songs and tons of different Playlists on my iPod Classic that I want to be able to transfer to my iTunes app on my computer so I can manage everything and add to my other iPods that I have... HELP!!!

Thank You!