First time I've seen a sleeve worn to the point of splitting.
The split on the sleeve was from the removal. Light tapping with a cold chisel. The sleeve face separated and was free floating in the hub. This probably helped caused seal failure. You can see the sleeve face in the first pic lose in the hub. I tear them down each winter, you never know what you might find.
Wayne
The nut should be torqued to 18 inch pounds.