M1008 rear axle lube

Hey guys. I'm planning to change the gear lube in my rear axle since it looked pretty sludgy when I pulled the axle out. Anyway, can someone confirm that it only takes 2 liters to fill it? Seems kind of low, but that's what the manual says. Also, is there any sort of drain plug anyplace, or do you pull the diff cover?

Any preferences on brand of lube? I was thinking of putting Mobil 1 in, since I have some of it laying around.

2 liters sound's right, any brand should work as long as it the right weight.