80w-90 gear oil? SL-5 or sumthing like that?

 

Yup 90W gear oil

I recomend GOOD synthetic. If you get Mobil 1 or other good oil it will already have friction modifier in it (assuming you will need it for an LSD)

 

Transmission should be GL4 oil

Diff should be a GL5 oil



if you drive your car in the winter and it is cold enough for it to snow you need to run 75W90.



Else if you live in texas 80W90 is what you want.



The oil viscosity applies to both the trans and diff. Check your owners manual