As Fred said, the whole carrier assembly unbolts from the axle, rather than than having the differential attached to the inside of the axle housing. It's heavy, make sure you have it well-supported before unbolting it from the axle. I've pulled one in free-fall (junkyard doesn't allow jacks), and I narrowly avoided being hurt.
The axle itself is nearly indestructible, I wouldn't worry about hurting it - and bearings and gaskets are still readily available.
