Inside was the coupling that connects the gear box to the generator. What I saw was not pretty.
After some wrenching I got the parts separated and just knew this was going to be a learning experience. The parts on the left are the worn out Browning three pin coupler. One pin in each half had worked loose and started to wear the holes. I would learn about Browning, Dodge and Lovejoy couplings, solid and thru spiders, plus their load torque ratings. I selected a Lovejoy sized to handle a lot of torque load.
Good news on the torque. Bad news on the fit. Looking thru the inspection hole there was no way to tighten the 5/32 set screw. A thru spider would have lowered the torque so I went for the next size smaller coupling and made the fix.
Last but not least. Do you see that blue dot on the back end of the generator? Now you would think I was done and had learned my lesson. Not so. So I pulled the blue plug out to have a look and sure enough, this coupling was also bad. However this time it was the key and keyway that were worn. The set screw had worked loose and the key wallowed out the keyway. After some head scratching and web searches I decided to go with a new key and Loctite 660 and make the best of it. After I put it together I bench tested it with 10 one minute run cycles and it was still tight.
I ended the day by making some nice bird proofing screen grills that will keep my feathered friends out of the nacell in the future. Wheeled the unit down to the base of the tower and mounted the blades. Tomorrow I'll call and schedule the crane.