Belt dressing is a band aid solution. About the same as tossing a can of "Restore" in an engine and hoping it will last another 100,000.
These trucks have a self tensioning serpentine belt system. If it's "squealing" something is wrong.
You can have a pulley or rotating component going south (causes the belt to squeal from being dragged over it) your belt can be old and glazed or stretched (ie: time to replace) or perhaps the tensioner is not doing its job anymore.
Find the cause and fix it, don't just treat the symptom.
That will eventually bite you in the butt....