I just got my Strange 12 bolt rear end in and it doesn't seem to have oil in it and on the break in tag it just says to use non synthetic gear oil with additive but it doesn't say what grade oil to use. It has the 4:11 gears, heavy duty posi, 33 spline axles, etc. Anyone have any ideas on this or should I use whatever grade my 10 bolt use to use? thanks

Myles