[mwonter]

Does the ipod info display correctly on the MyLink when the car is in park, but not while it's in gear?

This is said to be a safety interlock to help you keep your eyes on the road. I didn't find a good answer about if this feature is disabled if you have someone, or a sandbag, in the passenger seat.

Otherwise, here's a link to a discussion thread on the ipod vs My Link issues, may provide some clues, from a Chevy Colorado owners group.
http://coloradofans.com/forums/201-2...-firmware.html

Could also be a need for a firmware update, possibly for both the ipod and the MyLink.

Then there's this:
Why won’t Chevrolet MyLink index my music from my USB?

We recommend that there be no other files on your device when playing music or downloading any data. Any other files could interfere with the system properly indexing your music. We recommend that your USB thumb drive† be formatted before loading music and pictures. Some USB thumb drives have special security or encryption software; this software may prevent the device from being recognized. In addition, the system might not support that format of device.

Here's the link I found that at: http://www.chevrolet.com/2014-mylink-radio.html

Once again more info, better answers. Make model and year info would be helpful, but not to me, I'm out.
Good luck.