Getting ready to change the rear diff fluid on my 05

Hey guys i am getting ready to change all my fluids. I have a few questions about the rear diff. At my work (advance auto) our computer says that it takes 75-140 gear oil, with a Limited slip additive. The additive is only necessary with a LS diff correct? The computer basically calls for it no matter what. Also when searching online i see some people saying to use 80-90 i think. So what is the PROPER fluid to put in this

Truck is a 05 4.0 with a 8.8 4.11 open rear end