Trouble adding Audiobooks in iTunes 12.1.2.27 with OSX Yosemite 10.10.3

Hello, I am having Trouble adding Audiobooks in iTunes 12.1.2.27 with OSX Yosemite 10.10.3, I downloaded 4 Audiobooks from Audible, Synced my iPod but the new Audiobooks do not show up in either the Audiobooks or Music section of my iPod after I sync my iPod, I do see them in the Audio section of iTunes but not on my iPod, any help would be greatly appreciated. thank you Michael