I initially thought the keyed section was a nut, but the thickness of material at the bottom of the key seat would be extremely thin, is why i sugessed it comes off the other way. But honestly no offence to OP but it should be very simple as to how ot comes off. Clean it off and inspect it. Its sich a simple part. If you cant see how it comes off start tryin ****. Put a pipe over that ***** and whack it a few times, dont mushroom the shaft. See if it moves, if not go the other way. If you mushroom shaft file it down. If you needa go the other way clear the way to remove gear, if you heat it you might soften it. If you heat it dont get it very hot. Loctite only takes about 200c i believe to soften it. It shouldnt be too hard. Try using a punch and hammer see if that keyed secrion is a nut, Like i said in my earlier post look up the pqrts stack up if your having problems. Ereplacementparts.com