AH64ID
TDR MEMBER
Your call but no reason to use anything other than 75-90
Unless you are towing heavy.
Even then my conversations with AAM indicate that nothing other than 75w-90 is needed unless one tows at/above GCWR thru Death Valley all the time. The engineer I spoke to was very confident in their axle and 75w-90.
75w-110 is a nice tweener for folks wanting a little more, but for 99% of people I don't think it's warranted in this axle.
I've never seen anything in writing from AAM or Dodge/Ram indicating anything but 75w-90 for the 3rd and 4th gen axles. Dana had a different opinion, then again it's been a lot of years since Dana was used and there have been fluid and machining improvements since then. Heck the '19+ cummins calls for a 10w-30. Times are changing.