The search isn't working and I'm missing my manual. I need to change the gear oil in my axles. I've neglected doing it, and I've never done it. Am I right in thinking that I will have to take the whole cover off to drain it? Then I assume I will need to scrape the old gasket off, and put a new one on. I would also guess that it needs filled back up to the "plug". Is there a new cover I can get that has a drain and fill plug? I did some searches and it doesn't look like it. How often is it recommended to change it? What weight(s) would be good for Phx Az winter and summer's?