the teeth look to be chewed up or something...maybe they're not meshing correctly and that's why they slip? Corners rounded off?
i just talked to the detroit tech guy and he said the thrust washers can wear down enough to affect the locker. recommended putting new ones in when you put the locker in for future reference. i asked him how thick they should be and he didnt know. i gotta pull it, put new washers in, and try it again. if the teeth are rounded its warrantied up a 32" tire. my dad runs 31's.
could those springs in the locker be worn out?
1976 F-100 Kustom Krawler
1976 F-150 Custom
1964 CJ5