I had one trash out at 85,000 miles..It caused a massive ticking sound, like bearings in a compressor or alternator going. I couldnt figure it out....till I read bout it somewheres. Mine trashed out early probabaly because our PTO setups run off that pulley, and add alot of force on the crank pulley. When I undid the PTO belts the pulley pretty much seperated...It was like 80 bucks for a new one from GM..I have heard alot of these failing myself......If I didnt have the PTO belts holding the pulley on...she would have gone right through the radiator. Bill