I recently purchased a new second hand Muir Atlantic 850 winch photos below
Its packed ready to go on Monday for delivery to me . But whats puzzling me is I think it should have a gear box mounting flange so when the gear box is slide into place as well as a cir clip on the shaft to retain the gear box it is also mounted under the deck .
To me looking at it if I powered it up the gear box would turn on the shaft
Just had a thought Dr rog posted a couple of photos a while ago Ill see what I can find

in this photo you can see a flange coming off the gear box