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Replacement parts for GSD5560GSS models | AppliancePartsPros.com

I would remove the sump cover and check the sump for debris.
Note how the inner piece goes in, put it in the wrong way and the chopper will eat it.
Be careful often there is glass in the sump.
Also check that there is not something wrapped around the motor's chopper.

Also remove the kick plate and check if something has come loose with the motor mount.

Cannot hear the noise so it is hard to tell what it is. I have a similar dishwasher just older without a seperate drain pump. From day one it has made a rumbling sound at the start of the cycle and between cycles. I think it is because the main pump is cavitating (sucking in air) when running in a low water situation.