For the 2011 Jeep Grand Cherokee with the 3.6 L V6 use SAE 5W-30. However, if you have the Hemi 5.7L V8 you must use SAE 5W-20 for the MDS to function properly. I have been using Mobile One 100% Synthetic in all my vehicles for over 20 years. I live in a cold climate and Mobile One 100 % Synthetic is critical for starting when the vehicle has been sitting out in -30 C (-22 F) for long periods. Synthetic oil is also critical at the other end of the temperature spectrum. Stop and go driving in high temperatures such as 35 C (95 F) and above causes the engine oil to thin out. Just remember, if you have the Hemi V8 use 5W-20. Change the Oil filter every time you change the oil. If you have the 3.6L V6 which has a cartridge filter mounted on top of the engine you need to follow the steps outlined in this PDF file:
It is important to have a funnel when adding oil to the V6 oil fill pipe located on the right side of the engine cowl. It is a small pipe opening and if you try to pour from the oil container into the mouth of the oil fill pipe you will probably get oil all over the engine. Get a small funnel.
Good luck with your Jeep 2011 Grand Cherokee. I have found my 2011 Jeep GC to be the best performing Jeep that I have had over the years and I have had a lot.