Update:
I finished pulling apart the tranny today and when I broke the rear section(center diff housing) loose from the main tranny, out fell the other two shift inserts like the one pictured above. When I split the main tranny housing and inspected the main shaft nut, it was staked correctly and doesnt appear to have moved. I also am at a loss to see where from and how these pieces fell out. I am guessing cycling the gears opens different gaps along the shaft and maybe in its current setting I cant see the part these would come from.
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