Rear Differential Question

[philosophicaldreamer]

Somebody has told me that I should consider having oil changed in my rear differential. I had my bevel-gear oil changed, but I had never thought about the rear differential. Should I attend to this? Can I change the rear differential on my own, or do I have to go to a mechanic? What oil should I use if I can do this job on my own? Any input will be very appreciated.

Ta-ta, j.