[tonybunce]

I have a GTS22JBP that is about 6 years old.

About 18 months ago I replaced the evaporator fan motor because of a loud vibrating noise coming from the freezer.

Well the noise has returned and I think the evaporator fan is the cause again. I have taken off the ductwork in the freezer and it is apparent that the noise is coming from the motor/fan.

Is it normal for the fan to be replaced this frequently? Could there some other problem that is causing the fans to fail? Could the real issue be with the motherboard? If so what is the best way to test that theory?

The "evaporator fan motor test and replacement" threadsuggest adding a "round slinger/umbrella" to prevent moisture damage. Any suggestions/guidance on how to do that?

It also looks like the Supco SM999 is an generic replacement option vs the official WR60X10257 part. It looks like that is quite a bit cheaper (about a 3rd of the price). Anyone have any experience with them?

Anything else I'm overlooking?

[richappy]

There is no motherboard in this,you are lucky.
Your problem may just be worn motor endbell rubber gromets which allow the motor to shake loose. Just add some rubber gromets,
Have used the SM999 motors, they are cheaper, and more reliable,but draw a little more current.
If you do use one, make sure to use light weight, non-detergent oil on both bearings. Failure to do that will limit it's life.