GE side-by-side; 13+ years old but still works good.

However, I noticed that the refrige was only about 42*, so I began lowering the settings and found that the freezer will get very cold, but the refrige will not gett below 40*. I've read where 37*-40* is good, but I'd like to get it around 37* (good cold beer).

Any suggestions as to why this is happening?

If the freezer is getting plenty cold then it is simply an issue of getting the cold air to the fridge and keep it from leaking out.

So it is probably one of three things.

1) The door seal to the fridge is not tightly sealed and warm air is seeping into the fridge raising its temperature. See this article for more info:
http://acmehowto.com/howto/applianc...orsealcheck.php

2) There is too much stuff in the fridge resulting in inadequate air circulation. Remove some food and make sure the vent from the freezer is not blocked.

3) The vent from the freezer to the refrigerator is blocked. It could be an ice build-up, it could be grime or the freezer could be over filled and blocking the vent. First locate the vent. Determine what is preventing the air from flowing through and then remove it. If it is an ice build-up and your freezer is a frostless model, then the drain tube is probably plugged. See our fridge section on www.acmehowto.com to learn how to clear it.