This is the chopper motor from the 1003 Thunderbolt that was in my garage for the last 7 years until last December. The city of Sherman took the siren back (very long story) and ended up putting it up for auction. I just couldn't let it go so I bid on it and won the auction. I believe this siren is a early/mid 1970s vintage.
I never took it apart (other than rotator box covers and solenoid covers) because it technically wasn't my siren. It was "officially" on loan to me for my web site from the city of Sherman Tx. but I knew it was probably in good condition inside judging from the condition of the inside of the solenoid housing. It always ran perfectly whenever I hooked it up.
I took it apart today and was happy to see that it is in even better condition than I thought it would be. The grease down in the chopper tube is still wet and not even dried out.