What was the condition of the grease when repairs were made? Any indication of insufficient grease, oxidation (color change), or water? What did the bearing look like after removal? What faults were present (photos?)? Any indication of EDM from stray electrical current, if motor has a VFD control? The grease filler tube has to be full of clean grease before any measured amount can be added to the bearing housing. I have a lot of experience with ACC fan sound and vibration problems and some gearbox failures.