vibration feels like hubs are stuck in

[wrenchinup]

On the highway my 97 4 WD 2500 feels like the hubs are stuck in, when in two high, so I jacked it up and found both wheels are not freewheeling. They aren't turning. So I'm pretty sure they are stuck in, but I've never had a "Center Axle Disconnect" front axle before so I'm not positive. From what I can find, if the vacuum motor doesn't work right it fails to engage the wheels. Anyone have any experience with the vacuum mechanism causing wheels to stick in the engaged position? Thanks

 

[CVX20]

Vacuum switch is more than likely stuck.I'm actually not that familiar with the Dodge set-up but most have a vacuum switch on top of the transfer case right behind the shift linkage.