Hmm...
If it's like the early King Air, and I bet it is, then that emergency gear extension procedure requires that you pull a little folding handle and turn it 90º before using that long handle. If you don't get that right then you can yank on that long handle all you like, but it will not have been connected to the gearbox for the landing gear. We had a fellow find that out the hard way, with somewhat similar results.
I was once in a similar fix in a Cessna 303, lacking one green light, with the emergency extension gizmo nowhere in sight, so that I finally just did a very gentle landing, when the green light came on. It was just an indication problem.
Upon investigation, it turned out that the device I was looking for had been covered by the new carpet! How stupid would I have looked if the gear had done a partial collapse?