Use a nickle rod and stick weld it. Empty the gear oil, reinstall the cover, use a vaccum pump for a a/c system to pull a vaccum through the vent, Clean the area to be welded with starting fluid while pulling a vaccum. Weld the axle tube to the center section while pulling a vaccum with the nickle rod.
This works every time, but I have never seen a 60 do this. I usually have to do this to chibby 10/12 bolts. Realignment could be a factor if it is excessive.
SteveinAZ