Hi folks. I Just purchased a used Echo EA-400 w/8" auger bit. It seems to be in very good condition except there is a clacking sound when revving under no load. I don't know if this is normal because this is my first auger. I haven't drilled any holes with it yet so I don't know if it would do it under load. The clacking frequency seems too slow to be coming from the engine and seems to be, more than likely, coming from the gearbox. I did hold on to the output shaft with a rag while revving in an attempt to apply light resistance to remove any slack in the gearbox but still can hear the noise. Thanks in advance for any help!