4WD Vaccum Lines

I have a 1990 4.0 XJ with the 231. My vaccum lines are rusted out and broken so i need to replace them. I am at college right now and cannot get out to the Jeep to check this, and yes i have done a search. What size rubber vaccum line should I buy to replace the old lines. I will replace straight from the transfer case to the vaccum shift motor. Thanks in advance.