Should the front drive shaft on a 2006 dodge 2500 turn while in 2wd?

No, the front driveshaft on a 2006 Dodge 2500 should *not* turn while in 2WD. If it is turning, there's a problem. This could indicate a problem with the transfer case, the front axle disconnect (if equipped), or a binding issue somewhere in the drivetrain. It's important to get this checked out to avoid further damage.