To replace the left side axle seal you need to remove the differential carrier and bearings.
To replace the right side you need to remove the axle shaft and axle vacum disconnect.
In both cases special tools are required to install the new seals.. It would be very tricky to get them in (so they don't leak) without them. I can get you the tool numbers if you'd like, they have to be ordered through SPX / Miller. The downside is the tools will likely cost more than paying someone to do the repair (although you can probably get most of your money back selling them on Ebay).
I hope this helps, any questions don't hesitate to reply back and ask!
I apologize for jumping in, but I have had good results in the past using a piece of all thread with appropriate sized washers and a couple of nuts to draw the seal in place.
I did this all the time in the days before I worked at a dealer and had access (if I could find them) to special tools.