Chevrolet Repair: Water Pump?, raditor, serpentine belt

Question
I have a 1998 Jimmy with the 4.3 engine.  I have a very bad squealing sound, in the front of the engine behind the raditor, once the RPMs go over 1500.  I've changed the serpentine belt, Idler and tensioner.  Squeal still there.  Water pump shaft not loose and no leaks, but noise definitely in that general location.  Any ideas?

Answer
a squeak?? hmm. i would replace the water pump, odds are its gone bad, but at least thats not too expensive. hope that is whats wrong with it because if that doesnt fix it.... i hate to think of what it could be....check all fluid levels just in case.... and let me know what happens.