It does not demonstrate successful pumping. Continued inflow can create an overflow while the unit remains unable to do its job.
What the observation means
A hum can have several causes and is not proof that a particular motor part should be replaced. Opening the casing exposes electrical and contaminated components.
A useful next step
Stop connected fixture use and arrange assessment. Record the sound and what the water level did. Do not hold a switch on, strike the unit or repeatedly restart it to free a suspected obstruction.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.