Hi. I am new to TrailVoy so hope I am doing this correctly! I have a question: I have a 2004 Trailblazer EXT 4x4 4.2l. There is an increasing noise coming from the AC clutch - think or the pulley tensioner (lifter?) Can I just replace the bearings in the clutch or do I have to shell out the whole $500 for the sealed unit that Chev is trying to get me to buy? Thoughts? I look forward to your thoughts.