yes sounds like your slave cylinder,JK clutch hydraulics is a servicable system,their is a bleed screw on top of the rear of the slave cylinder,it shares a common resivoir with brakes,make sure mastercylinder res.is topped up with dot3 brake fluid,locate bleed screw on top of slave(it is a tap style,do not even need tools)and bleed just like you would your brakes.
why did system suddenly become aired up/low on fluid?inspect line between master cylinder and slave for rubbing/leaks,and viually inspect slave(and bleed screw)for leaks.

 

I got it towed in (roadside assistance) to the dealer and it turned out to indeed be the slave cylinder. They are taking so long 'cause they had to wait for a new part from Dallas. I am not sure why they didn't just rework it...maybe the housing was busted or DC has a new part # as it seems a good number of folks are having this fail prematurely.

As far as it going bad, it went pretty quickly...one press of the clutch and all was well with the world, the next about 100 yds to the next stop light and it was all but gone. Since it is still under warranty, I just let DC pay for the tow and work. I'm just out a Jeep for a few days

Edit: If anyone is interested in knowing, it turns out it is a new part number after all from DC. Apparently it comes as a "pre-charged" (read: no need to bleed) system that goes from the pedal to the transmission. The service adviser also said that it does not share the same system with the brakes - it is an independent system. I read someone say that they share. That would be a bad design as you'd most likely lose your brakes as well with a leak, etc. Just went and picked it up a few minutes ago.

 

a slave cylinder is just like a starter or battery- they work great- UNTIL the LAST TIME.........