William.....I used 85/140 w gear lube.....combination synthetic and petroleum.....If I remember correctly, it took three and a half quarts...(don't hold me to that.) It's not all that expensive, and you may need to go with another "weight" considering your local weather conditions......Just remember to check the level after you've driven the car for an extended period......the oil level will drop as the lube is sloshed into the swing axle tubes for the outter bearings....I used a valvoline lube, if I remember correctly....
Good Luck...