fastwoman i would def recommend you add some lucas oil stabilizer to the oil in your diff and transmission, especially in cars this old, that stuff is amazing

bryand2, the diff drain and fill plugs have 1/2" (12mm?) square male and female facings on them. The drain plug is on the bottom, and the fill plug is on the backside, about halfway up. When you fill it back up, you'll have to perch the filler spout over the moustache bar and squirt about 1/2" through the air, into the hole. (Fill until oil starts pouring out the hole.) I forget where the fill plug is on the transmission, but it should also be about halfway up. Drain plug is obviously on the bottom.

My oil is already in the diff -- Mobil 1. I'll look into the Lucas for the transmission. Thanks!