GM-GMC: high pitched squel, clutch components, clutch release

Question
I have a 2001 gmc pickup, 4.3L V6 manual transmission and it developed a high pitched squealing sound that comes and goes, it occurs driving, coasting or idling and doesnt matter the rpm. I did notice that when it happens that it will go away if i press the clutch down, even only a little bit. I changed the fan belt and i dont think its the altenator, Thanks allen

Answer
I think that you have answered your own question.  The problem is with the clutch components and is most likely to be a bad clutch release bearing (also called a throw-out bearing).

If you take it apart to replace the bearing, be sure to have the clutch checked and replaced if necessary.