ELSD only comes with quadra-drive, does your EVIC display Quadra-Drive when you push the start button? Does the rear diff have an electric motor hanging off it similar to the one hanging off the transfer case? You should see AWBP and DSFP on the build sheet for ELSD.
The 36,000 mile fluid change is for severe use. If you routinely take the Jeep off road through mud and water or tow heavy a lot, then change it, otherwise just check the level.
2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6, 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
Change it you will be amazed at the amount of debris floating in the fluid. Gear oil is cheap and it is 10 minute job to change it, just buy a outboard fluid pump with threads onto a qt bottle.
Dont forget your t-case too. I wouldnt want to leave all the metal floating around in my diffs for 36K miles, no thanks!
I used redline GL5 75w-90, technically the jeep comes with the 75w-85. The redline has the additive for the diffs in it.
Lots of pearl in those and that was the second change and my jeep only had about 1600 miles on it and the batch of gear oil only a 1000. Diffs shed a lot of metal breaking in. I will probably go another 5K or so and change it next spring and see what it looks like.
If your at 36K, I would change it with a good synthetic and your probably good to go for a while.