You hub is missing the internal gear...
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Really ?! That's how I found it both sides.
It looks no different to the one @Rumcajs posted ...
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Good luck with locking your hubs then. Unless the photos is deceiving. I see no internal gear in there.
The gear standing on it side I cant see in your pic.
Attachment 72972
The plate with the two humps on it is on top of this gear. Right in the centre of the hub is an internal spline which sits on the axle shaft, that spins freely when unlocked, or in auto position. When you lock the hub, the gear you see in my pic is pulled down and the external spline of this gear messes with the large internal spline in the hub(can see it at about 3 o'clock in my pic) there for locking the outer to the inner section. I would say its all in yours, the pic you have just doesn't show it well.
Heres a pic of my old auto hub in the unlocked/ auto position. The entire inner part of the hub spins free until the gear is lower and locks into the hub.
Attachment 72973