Originally Posted by meyers
I wouldn't use WD40 on the belt. Rubber and petroleum based products like that aren't usually a good mix. Go to your local parts house and get some Belt Dressing or silicone spray. Or just change it out takes like 10 minutes..
Belt dressing quiets them down, but I've heard from a mechanic friend of mine that it isn't good for them either.
OP, if lubing the belt makes it stop squealing, then it's time for a new one... Gatorbacks are very good belts. They cost more, but they are nice and quiet. If lubing doesn't help it may be the tensioner pulley going out.