Grundfos MQ3-45 - Weird Noise plumbing advice

Grundfos MQ3-45 - Weird Noise I have a Grundfos MQ3-45 feeding my domestic water from a ground level tank (filled from an RO system from the well). The pump is about 4 years old, with normal-heavy household use. Today it started making a bit of an awful noise - see the attached video. I disassembled the hydraulic end of it to see if there was anything odd there, but it was all normal.

Any ideas? I would like to avoid spending $1500 on a new pump, since I think these should last a bit longer than this... is it repairable?

Thanks

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