[thefro526]

Perhaps I'm playing devils advocate here but, 816 used one of these transmissions in 2009 without supporting the end. But, we also cut down the shaft so it was only long enough to go through a piece of 1/4" Lexan and put a sprocket on.

I'd say depending on the application you might be able to get away without supporting the end of the shaft if it's a light duty mechanism and you keep the load within a half inch of the gear box.