One problem related to differential unit has been reported for the 2015 Jeep Wrangler. The most recently reported issues are listed below.
After noticing a accumulation of fluid under my vehicle I took the car to a mechanic who mentioned that the seals on the rear axel were both leaking. I took the car to the dealership where they verified that both seals were leaking and that the differential cover was also leaking. They replaced the seals and resealed the differential cover, but noted that I was responsible for replacing the fluid in the differential. The vehicle had not been taken off road, outside of usual driving down unpaved roads.