It states in their website that 5W-20 is Chrysler approved.

 

Yes I use 5w20 ams oil synthetic xl been using since day one. Just keep all receipts of oil changes.

 

Tons of people use Amsoil. Tons of people use other brands as well.

 

I have used Amsoil. Is is a good motor oil. However, I use Mobile 1 or Penzoil Platinum currently just due availability and price. I change my oil regularly and don't race my Jeep. Rpms are rarely over 3000 and my oil temps don't get very high so any of the quality synthetics will do well in a JK.