The drain hose or water inlet hoses may be knocking against the rear of the washer cabinet. Secure the hoses using the beaded strap supplied with the washer (on some models), or use a wire tie. The vibration of the washer can be carried through to the hoses. Also, as water is pushed through the hoses, it can cause the hoses to move. If the hoses have enough space to hit the cabinet, a knocking noise will be heard. See the Installation Instructions for details; use our search feature below to find the manual for your particular model.
There will be some noise during the drain portion of the cycle. This is normal. During drain, the washer pump will continuously run to remove the water released from the load. Due to this continuous running, the pump will remove most of the water and then pump air. This is normal, but may cause a gurgling sound. You may hear a continuous humming sound with a periodic gurgling or surging sound. If a lower water level is used, the pump may make sounds for a longer period of time. The drain portion of the cycle usually lasts 3-5 minutes.