My 2000 Blazer has developed a whine in the rear when you push on the gas; i.e. when the drive train is under load. The whine tends to diminish or go away when you let off the gas and coast. I had a differential fluid leak which I fixed, and then refilled the differential with new gear oil; but the whine is still there. I am suspicious that the pinion gear bearing might have gotten worn when the fluid level was low. Or, that the pinion and ring gears might be worn - although there were no filings or obvious wear spots on the gears when I opened it up to check it out and replaced the gasket to fix the leak. Is there a way to differentiate the source of the whine; i.e. pinion bearings or gears. And is the bearing replacement a difficult project? From what I've read I don't think that I want to mess around with the gear replacement. Thanks a lot.

Cars & Trucks - Chevrolet - Blazer