Hello, I suppose that your washing machine is one of the automatic ones, in this washing machine you comment that the transmission or box is new and that you have changed the capacitor and the motor does not have force, in this case only the engine that for some reason is malabrored remains . One of the failures by which the engine is blocked is the transmission that being hard and not turning the steering wheel, the engine does not turn and buzzes. Another defect for which the motor does not rotate and hums is due to the capacitor in poor condition. You can test the motor by taking out and testing directly, connect its capacitor terminals and connect it with the test leads to the current, the motor must rotate freely and forcefully, then change position and verify the other turn and the same must start and have strength. Failure to start or not have the necessary strength is the engine that has failures.