Its not the same diff but this video explains how to build Schumacher Ball diffs pretty well.
What I have found that in the area when you are tightening a few turns at a time, I use my Bosch iXO cordless screwdriver to bed the balls in with a about 10-15 seconds each time, then when the diff is fully tight with all springs compressed, then back off 1/4 of a turn (it says 1/8th in the video anywhere between will suffice) and then put a cone point grub screw in the other side.
Then when the grub screw is up against the end of the diff screw, against it but not very tight at this point, tighten the main screw down onto it, I normally use a spanner in the slots of the outrider to hold the other side.
Other tips include making sure that you have the Small Race Washer in the end of the thrust assembly correct, if you have the large one in the wrong place it will bind against the outrider causing the diff to come undone, I have seen this when rebuilding other diffs.
Some people have been tempted to put thread lock on the screw, I personally wouldn't do this, the locking of the main screw with the cone point grub screw is sufficient enough.
My KD Diff initially I made some mistakes, however I have rebuilt many diffs, now and confidently say that they do not come undone and perform well, and ultimately are the same each time.
Hope this helps
