Coupler broken?

[Karl2]

Picture below shows the coupler on the PTO extension that drives the chain sprocket on my snowblower. Yesterday I caught a big rock in the blower and now this coupler spins freely as if there was a snapped shear pin but I can't find any. Main PTO shear pin and extension pin are fine. Zerk makes me suspect there is some sort of clutch inside the coupler. Anyone knows if these couplers are designed to fail if shear pins don't snap when excessive resistance is encountered? If so is there a way to fix the coupler or do I need a new one?

Thanks in advance!

 

[Karl2]

A'right, looked around and my guess is that the coupler comprises a torque limiter. Couldn't find a way to reset it though.