Remove axle on Honda HT-R3009?

I'm trying to restore an old HT-R3009 mower. I was able to get it running again, but now I'm looking at the reason it was given to me for free. It just stopped going. I jacked up the back end and found that the rear right wheel spins freely. When I took off the wheel, I noticed that the grooves that usually make the wheel turn with the axle were worn down so much that he wheel would spin without the axle moving.

I see that there are connections on each side that look like I can disconnect to replace the ends of the axle. However, I'm not sure how to get them to turn. They seem to be rusted pretty good. I'll attach some pictures to show what I'm referring to on the axle. Also, the left rear tire is stuck on the axle. I've tried Liquid Wrench and light tapping on the back side of the wheel, but no luck. I don't want to damage the transmission by beating too hard on the wheel while it is still attached through the transmission. If I can get the axle to separate on that left side, it would probably be easier to get the stuck wheel off (the tire is dry rotted).

Any advice on how to get the axle apart or the left wheel off would be greatly appreciated!

I couldn't get images to attach to this thread, so I've shared them here: http://ift.tt/1Z14tTW

Thanks,
Trey

Remove axle on Honda HT-R3009?