It’s normal to hear a clunking noise as your washing machine shifts from one stage to another, such as from agitation to spinning. In this case, a clunking sound is normal and not a malfunction.
If the sound is rhythmic, the cause may be a heavy item or foreign object in the drum. If you suspect this to be the case, stop the machine and drain the water inside to remove the object.
If your appliance isn’t operating normally while making this noise, contact an authorised service agent.