Need Help -- 635 Differential Oil Change

[pbonsalb]

The 3.64 LSD in a modified 79 635 that I am working on has a round container mounted above the oil fill plug on the side, with a tube going into the oil fill plug and another going into the top of the differential. How do I refill the diff once I drain the oil? Do I remove the round container? Is there any trick to it? Do I fill from the side or the top?

Thanks,

Philip Bradley