2006-2008 Dodge 2500 Diesel
Removing the belt can be done with a half inch ratchet with a short extension. The center hole on the tensioner pulley is a half inch hole.
Using the ratchet, rotate the tensioner pulley and slip the belt off of the water pump. Slowly release tension to the tensioner.
Route the belt according to the diagram above around every pulley except the water pump. Once you have aligned the belt on all the pulleys, rotate the tensioner and slip the belt on it.
Be sure to inspect the pulleys before installing the belt. After the belt has been installed, be sure to double each and every pulley to make sure it is aligned correctly on every pulley.