Something is wrong or there wouldn't be a light on.  Try a different Jeep dealer, or an independent mechanic.  Many dealerships don't want to get involved in warranty work as it pays less.  When I was a Dodge service advisor, Chrysler paid around $64/hour for warranty repairs, there was a fixed diagnosis time allowable, plus there was a more involved process for receiving the money and claiming the parts.  Dealership charged Joe Customer $76 per hour, and he had to pay for parts and labor upon picking up the vehicle.  If we were busy enough with Joe Customer work, the service manager tried everything he could to AVOID doing warranty work.  Not right at all, just letting you know how it works from the inside.  A more ethical dealer may be willing to help you out.

agreed, my brother works for a very large Toyota dealer and it is the smae everywhere. Try another dealer

Mine did this for a few minutes before my battery went quit working, it's crazy but it didn't show up again after i got a new battery! Maybe you could
have your battery checked for free at a car parts store, before you go to start your car and it won't start like mine did :) Hope this helps!

Go to advance auto parts and get them to put a code reader on it. It will help narrow things down. It might be mileage sensitive light to tell you to change the fluid in the transfer case.