Hi,
I just listened to the video again. That sounds like your starter motor. It stops when you place it in gear because of its design. Either the starter motor is faulty, or something took the teeth off the flywheel.
We need to remove and inspect the starter motor. I suspect the Bendix/solenoid is not engaging the drive gear on the starter motor.
Have a helper turn the key while you listen near the starter motor area to see if that is where the sound comes from.
Let me know.
Joe
Tuesday, December 12th, 2023 AT 7:37 PM