A bloke in our MV club had a Marmon Herrington locking diff fitted in his MH Gun Tractor for a while. He took it out and replaced it with a standard diff, as the lockers can "click out" leaving you with no drive at all. He told me that sometimes you'd have to get out of the truck and give it a push and you'd hear it click back in and off you'd go. In his opinion, they'd be more suited to something running in 4x4 all the time.
Another bloke in our club has a Ford GTB which he converted a Detroit Locker out of a tractor to fit in the rear diff. Works a charm I'm told
