Sqeaking refridgerator

My refrigerator makes noises quite often. Some days are worse than others either with loudness or frequency. Sometimes it sounds like it is full of a herd of crickets.  It is driving Tammy crazy.

I don't hear it half the time as I am so used to it making noise.  If the refrigerator is quiet for too long I worry it has died.

I don't know how old the refrigerator is.  Since dad didn't leave a warranty instruction manual, the refrigerator must pre-date dad's ownership of the house. Therefore it may be from the early 1970s or 1960s.

Here is a 23 second video of it squeaking.

http://www.youtube.com/watch?v=0Lorpp3IYqI