My 13 year old fridge had a strange squeak to it. Thanks to videos on the internet, including AppliancePartsPros.com, a likely cause was the blower motor or grommets. Videos made it look easy. Opened up the back of the fridge and saw it in action. Motor had a VERY slow start. As it came up to speed, it shook, and that's definitely where the noise was coming from.
Looked up the fan on a few sites. Decided to get the grommets as long as I was doing it. Everything showed up promptly. Only had to remove two screws. One on the back cover of the fridge. One on the brace for the fan. There was another screw on the brace, but it was very difficult to get to and I managed to get the motor out with just removing one screw. Might be one of the easiest home repairs I've done. If I had to do it again, it'd be five minutes (once you pull the fridge out).
Parts are overpriced (Appliance Part Pros was competitive, so no reflection on them), but a whole lot less than a new fridge. Absolutely worth it.