transferring files to ipod touch

I have an Ipod touch, and am having difficulties transferring audiobook files to the Ipod. I have tried downloading into Itunes, then dragging the Mp3 files to the Ipod, I have tried transferring from Overdrive. The files can be found on the Ipod using the PC file system, but when I disconnect the Ipod, I can't find them looking at the device files.

via iLounge Forums http://ift.tt/1JWYdpr