Hmmm, no replies so I'll give it a shot.

If you download the pdf manual for the MCX at Horizon Hobby, you will be able to zoom in on the exploded view drawing. You will notice that the outer shaft is secured by the upper shaft locking collar just below the swash plate. Also, you can see the drawing of the outer shaft shows what appears to be a flat surface milled onto the end of the shaft that plugs into the gear. The gear center also shows the same flat surface, and there is no illustration showing any screws that secure the gear to the shaft. Therefore, I would assume the shaft is press fit into the gear.

Hope this helps.

DrS