One problem related to differential unit has been reported for the 2013 Jeep Wrangler. The most recently reported issues are listed below.
I was driving on city street driving 25 mph , when my Jeep Wrangler ceased immediately. Differential leaked fluid. I have also noticed the rear brake passenger side leak which I believe connects to differential. I brought it to a technician attention when I took my car to a recall and mentioned its not a problem. I had my children in my car. Could have caused a fatal accident. Lucky I was not on a highly driving 70 mph.