[Mike C]

Is this a half ton truck? You should be able to do seals without disassembling the brakes again. But you have to drain the differential and remove the spider gear pin in order to drop the c-clips and remove the axle.

Be careful rotating the differential case when you have the pin out as the spiders try to walk around the side gears and can come out along with their thrust washers. after pushing axles.

If you don't own one, buy a service manual. The GM ones are excellent. Pricy, but worth every penny if you are going to be your own mechanic.