It appears to be coming from the compressor, or close by to it, which is hot to the touch. It is now kind of a soft continuous "WHAzzzWHAzzzWHAzzzWHAzzz......" that was never there before. The pitch is the same as the tone you hear when the TV says "THIS IS ONLY A TEST"
Then every once in awhile it makes a gurgling sound like a dinosaur mooing faraway on the next block. Or maybe it's a lion. Reminds me of Jurassic Park.
That's in addition to the 'regular' refrigerator sounds, which is still running as usual.
Why can't they just put the model number on the front of a refrigerator? All it says is FRIGIDAIRE. On the back sticker there is Z174822C next to the schematic. LISTED HOUSEHOLD REFRIGERATOR OR FREEZER 125A.
I don't see anything else from your links or can find it off the web.
