Sure grip questions

If it's just the pumpkin you'd have to insert axles and see if you can make it slip but I'll tell ya even a worn out sure grip may not be easy to spin by hand.

There we're 2 types of sure grips used. The clutch type (stopped production in 68 but some can be found in early 69 differentials and it's possible to see one in a newer differential if someone swapped it in) and the cone type (69 and newer). The clutch type is rebuildable and a stronger unit (4 pinions vs. 2 for the cone type) but if your not racing a good cone type is fine on the street. You can tell them apart by how many openings are in them. The clutch type has 8 "windows" and the cone type only has 1 or 2 and you can see big springs through one of the openings on a cone type. The cone type generally doesn't bring as much money since it's a weaker unit and I have seen several cone types that we're complete junk. Their not considered a rebuildable unit like the clutch type but I as well as many other guys have revamped them by machining some off the side cones and shimming them up to get them to grip again. The housing and cones need to be in usable shape to do this procedure though. You can't buy any new parts for them but you can buy nearly everything for the clutch type so your nearly always better off with a clutch type