Moms with Refrigeration/electrical Experience

It's probably the compressor. Do what another responder suggested and vacuum it out underneath and behind. This should actually be done at least once a year. Are you having any problems with frost build-up in the freezer? Keep an eye on it...ours did a sound like this on and off for about 6 months. Because it wasn't consistent, I ignored it. And then it died the morning we were supposed to go on vacation. :( Just keep an eye on it...if you notice things not being as cold (or in the freezer, not as firm) have it checked out.

Good luck!

clean your back of your fridge on the outsid. the motor is working to hard due to dirt.

Sometimes you need to vaccuum out that part that has the kickplate (usually at the top or bottom). Who knew right? Happened to me once.

mine did this - turns out I had a big ice chunk forming next to the fan, so whenever the fan went on, it interfered with the blades of the fan. I had an appliance guy come to fix it, he had to take apart the whole inside of the fridge to get to the fan, then took out a blow dryer and cleaned it up and put it back together. Next time it happened, I did it myself, but I missed a few screws and put it together a little bit wrong, I think. Good luck!

it is probably the compressor kicking in.

In our current house, we don't have the ice-maker hooked up. So at times it makes a buzzing noise while it tries to make ice, unless we turn it off.
Good Luck

Happened to me too....vacuum under and behind!