Mine "dripped' oil for the first 6 months after "new" and when I checked the "LEVEL" fill plug, it would still spill out slowly !!
It's just an overfill from the jeep assembly, sometimes a little -sometimes a lot
Pull your fill plug and let it drain, till level with the bottom of the plug, do some wipe up and you should be OK !!
I've Never had any trouble with the rear diff. !!