Hard to say for sure without first looking at it, but I can't remember the last time I changed the complete sump.
Think the last sump I changed was because it was so built up with hard water deposits and could not be cleaned up.
Could be leaking some place else and the noise coming from the food chopper, but that would not be something I would commonly find.
Most likely a leaky motor seal and noisy motor.
Let us know what you find.