Pentair OptiFlow Repair/Replacement

Hello, running into sloshing/grinding/bubbling noise for first time on 3 year old pump. Cleaned out and lubed all connections, O-rings, impeller on suction intake end, including the pot and volute assemblies. No visible damage or water leaks. Only seal I didn’t check is mechanical shaft seal. Water temp is in 40s-50s. Could it be the cold? I also had scary bearing whining noise one really cold morning. But that has since stopped. Any advice on what to check next. Or what would be a good replacement pump for my Pentair CC150 Cartridge/Base? ThanksSloshing/Grinding Noise:

Whining noise, now gone:

Motor sounding fine disassembled:

Current Pump/Filter Cartridge Setup everything is 3 years old:

  • Pool: 24’ ABP, 14,500 gallons
  • Pump: Pentair Optiflo 2hp pump P/N 340078
  • Cartdrige: Pentair Clean and Clear Cartridge filter CC150
  • 20A dedicated electric line for pump
  • 1 1/2" piping

Update on this.  Ended up replacing the shaft seal as well.   Have a new volute part on the way.  But this pump is likely on its last legs.  I got it running but am going to hang on to it for a backup and get a new one.    Got some great insight and advice from Rich @Inyopools on my issues.  And picking out a replacement pump option.    Thanks Rich!