If you are sure the 4wd actuator on the transfer case is working, then either the hubs are bad or there is a vacuum problem to the front differential / axle. If the hubs are bad, they will usually make a grinding sound when they slip. If you hear nothing, then check to make sure there is vacuum to the front axle. If the axle doesn't engage, it doesn't matter what the transfer case does. It won't work.
Tuesday, January 12th, 2010 AT 6:31 AM