8 3/4 gear oil

regular 90 wt gear oil (or 85-90)... IF you have a suregrip, make sure it has the additives in it for that. I believe it is just shy of 2 qts... you put it in till it is to the bottom of the fill plug and it starts running out.... pretty hard to overfill unless you jack the pass side way up and leave the driver side on the ground.