Replaced fan and motor.Easy to do after watching video.
After doing the repair, I am convinced that most of the noise was coming from vibration of the fan housing itself, as neither the fan blade or motor shaft was loose. Some of the foam rubber attached to the mount had come loose.
But since I already already removed the old fan, I decided to complete the replacement
I would have appreciated having some strips of foam with the motor kit. I spent considerable time looking for a suitable replacement. I used foam mounting tape as a substitute.
The refrigerator is operating much quieter now.
Thank you for the great service you provide!