Locking hubs I assume. It's been years since I opened up one of those, but you don't have to remove the axles. And then it was on a 78 with full time 4wd which had a totally different hub assembly. Seems like there are allen head screws holding the locking hub to the hub itself, then maybe a snapring holding the guts in. Spindle nuts are round, with cutouts for a spanner or a carefully applied punch to loosen them, a lock plate under the outer nut, then an inner nut and then the wheel bearing. Take the caliper off first then the hub/rotor assembly. I think the rotor is part of the hub, so it will all have to come off and be replaced together. Damn,, I'm foggy on this, could do it easier than explaining it, hopefully somebody else will jump in here.
Alan has explained it right.The axles do not need to come out,but it is a lot of work to get to the rotors.You might want to check the U joints now,and ball joints,also look for seal leaks,you might as well replace whatever else is bad while your in there,it wont take much longer.
Its really not that bad. We had our 84 front end apart 2 weeks ago for rotors. Just remember how the hubs go back together and you will be ok.
Like Alan said, take the allen head bolts off, then remove the lock out assembly,then a small machine screw that retains the inner lock out assembly, next the spring, and gear that expends to meet the inside of the hub.
At that point there is a snap ring between the remainder of the parts and the hub. It is small and located along the inner edge of the hub. A dentil pick works best to get it out. Once that is removed then you will have access to the spanner nuts. There are two of them, remove the outer one, then the locking ring, and then the inner spanner nut. Once those are removed the rotor hub assembly will come off. Repack the bearings, and replace rear seal. Install parts reverse of removal.
Have fun, should be no longer than an hour per side. I am sure 2cd side will go alot faster than first one.