Thank you for the suggestions. The gear box has no bottom access. The shell will have to be lifted out of place to access the top. I will see if tightening the gear box screws helps.
The sound is not triggered by a magnet, it is controlled by the speed step for the engine. I should have turned off the sound when I made the video.
Wish me luck. Gunrunner John, I may need your repair services.
Sincerely, John Rowlen