I isolated the problem to the transfer switch. The generator output is fine, but the "output" side of the transfer switch from the generator has one side dead.
I agree with larrybell that the purpose of the transfer switch is to keep parallel feeding off of shore and genset lines, or worse a power feedback down the shore line to some helpless worker trying to fix the shore power.
However, a hard wire from genset to a 50 amp RV recepticle, then plugging the shore power directly into it when running the generator seems to me a more direct solution that is fool proof. That darn power transfer swith with all the connections, contacts, and circuit board, to me, is just a problem waiting to happen, and in my case, it happened (by the way, my rig is only 18 months old). And for the $650 it would cost to fix it, I can do the same thing for about $15 and have a more reliable power platform.
When I unplug from shore power, I'll simply plug the shore line into the genset plug when I'm storing the cord. Actually, this is probably good because it will keep the cord from moving around as much and protect the connectors on the plug end.
That's my story and I'm sticking to it!!!