If you will look on the parts break down there is supposed to be a bolt,lock washer, and a domed washer that secures clutch to tranny shaft internal threads! Same as all the other rear clutches. Hope were talking about the same thing??? What holds the inner and outer clutch sheaths are snap rings. I would say your misfortune is one in in a hundred?? Never had a clutch just "spin" off in 23 years,BUT yours as you say came apart,and I can see how it would put pressure on the outer bolt and washers. OPT