8.25 rebuild questions

I purchased a used 8.25 complete, 3.21 sure grip. I have it all down except for the sure grip unit. The Chilton manual says:
"The sure grip differential is serviced as a unit only. Under no circumstances should the unit be disassembled and reinstalled"
I take that is replace the bearings on the outside and leave it at that. Is there any servicable parts inside? I tested it when it was complete and there was no way to turn one side while holding the other. Clean it and reinstall ?
Also where can I find a adjuster lock screw/bolt, pinion nut,crush sleve and a set of spacers that go under the large pinion race without buying a whole kit ? I had the bearings,races and seals purchased already.