8 3/4 rear end worn out or not?

You can take them all the way out or use a jack stand to support the axle so it doesn't rest on the inner seal and just pull it far enoug to get the center out. If you have the clutch style sg, then get a new set of clutches, soak them in the additive, mark the case halves and undo the bolts that hold the halves together (they are left hand thread), pull apart the halves starting with the non ring gear side and keep the clutches in order as you pull them out, the the 4 pinion spider set up, then the other clutches. New clutches should come with instructions (follow them to the t), keep the inner splines aligned as best as you can, (easy way to do this is to stand 1 axles on it's studs and slide everything on that axle, now lay it on the ground, do the other side the same way) now slide both case halves together matching up your "mark" on the halves, and snug up the left hand bolts, make sure the axles slide in/out without any problem and torque to spec. Thats the long/short of it. Now reinstall everything, gasket, fluid, etc., do some figure 8's and enjoy the new found traction, or lack of, lol.