ADP
I recently learned something about my 10th gen alternator decoupler pulley (ADP). They are a mechanical where item that is recommended to be replaced every 120,000 km or 75,000 miles. Litens (Canada) is the OEM manufacturer for Toyota Corolla ADPs. I bought a Litens Pulley for mine and installed it. I would have bought a Toyota OEM if it was a part they offered. Apparently Toyota wants you to buy a new alternator if your ADP wears out. The old one was making noise and sometimes slipping - in winter when very cold (-30C). The previous owner must have also heard the squealing and popped the dust cap off and packed grease in. This is not the right thing to do - it has sealed bearings and the clutches will not benefit from grease, would only make it slip worse.
After installing it worked great. Highly recommend replacing this before doing the whole alternator. I don’t understand what Toyota is thinking by doing this. See picture for part number of replacement. The box says Gates but the pulley has the Litens name on it.