ID size of AT cooler hoses?

Hey guys,

Does anyone know offhand the correct interior diameter heater hose to buy to replace the transmission cooler lines on a '96 Grand Caravan SE?

During my last oil change I noticed the hoses were brittle and starting to leak so I want to change them, and it would help to have the replacement hose ready to go rather than having to pull one off and take it to the store to size it.

Also, replacing the hoses seems rather straightforward, but is there anything to beware of when swapping them out?

Thanks!