Cannot sync iphone with new itunes, what to do?

Hello there, Jake.

The following Knowledge Base article offers up some great information in regards to using an older iPhone without a service plan as an iPod:

Using an iPhone without a wireless service plan

Follow these steps to use your iPhone without a wireless service plan:

1. Insert the SIM card from your new, activated iPhone or one that was previously used to activate the original iPhone.
2. Connect the iPhone to iTunes on a computer connected to the Internet.

Once iTunes activates the device, you're free to use the iPhone as if it were an iPod touch.

Additional Information

Note: It may be necessary to repeat this process after updating or restoring the device.

Thanks for reaching out to Apple Support Communities.

Cheers,

Pedro.

Hello again, Jake.

Thanks for the update on your issue. Due to the nature of your issue you may find more information by using another one of Apple's support resources - https://getsupport.apple.com/GetproductgroupList.action to get a more hands-on response.

Cheers,

Pedro