Why is the tiller not spinning when the PTO shaft is?

Why is the tiller not spinning when the PTO shaft is?

It seams to be the part between the PTO shaft coming from the tractor and the gearbox on the tiller. From the looks of the diagram I found online it looks like the friction clutch assembly is just spinning freely around the shaft that goes into the gearbox on the tiller. Not sure what could be the problem or what part I may need to fix it.