WC15,
Sounds to me like the crane assembly (crane, cylinder, extractor) is what's falling out of your revolver?
If that is the case, there is a screw above the trigger guard that is supposed to lock the crane into the frame. That screw could be missing, or might have been replaced with a shorter screw.
The front of the crane stud that pushes into the frame, has a groove near the end. The crane screw is supposed to engage that groove when screwed in. The end of the crane screw has an un-threaded nub on the end, so it does not gall the crane stud groove.
In any case, you should have a gunsmith look it over.
The model 10 is one of my favorite revolvers, and I'm looking for another.
Bill