Have a delco starter/gen that has a high-pitched whine that paralells speed of engine. Charging fine. Could it be a bearing issue???? Has anyone ever run across this before??? I dont think it has been very long since it was overhauled, but I dont want to do it again if its not needed. I oiled the cups for the bearings- still noisy. I dont want to over-lubricate. Any and all suggestions appreciated.