Ok i had a hunch something was up with my truck cause my fuel mikeage has been down. I realized my front wheels dont ever unlock. I checked all my hoses and all looked good so i changed the solenoid on the firewall. Now on a jack my driver side unlocks nut the passenger doesnt. Now on a test drive the driver side actuator clicks. So, i surmise my passenger side is frozen and the drivers side is sticking and trying to work. Ive never heard any noise before. Anyway, i put the old solenoid back in so that the front wheels will stay locked and not click......so heres my question....aside from less fuel economy, i shouldnt damage anything with both hubs engaged right?

 

Correct. My wrangler's front axle shafts and drive shaft spun all the time.

 

Assuming your hubs are completely locked there is no significant damage beyond more wear. However they often don't break perfectly disengaged. Plan on changing both ASAP.

FWIW
I discovered by accident that I was in the same position. In that both of mine were nonfunctional. I have no idea how long they were like that.