Drum knock when spin cycle - Whirlpool Duet GHW9150P Front Load Washer

Check the drum dampers

Hello.
Noises are common when using a two-in-one washer and dryer, as clicking or whirring is part of the cleaning process during the transition to the next cleaning process. The GE Spacesaver washer and dryer combo uses a top-loading washer stacked beneath the front-loading dryer, and uses an agitator that makes noises throughout the spin cycle. Although whirring or clicking is normal, other noises or malfunction indicates a problem with the washer that requires minor troubleshooting. Professional repair is necessary if the washer continues to experience problems during the spin cycle, as there may be a problem with the washer's agitator.
1 Open the washer's door and check the balance of the load's clothes. Clothes that are unevenly distributed around the agitator cause excessive shaking and result in an imbalance during the spin cycle. Reduce the load's size by removing clothing if the washer's drum is overloaded.
2 Push "Start/Pause" to pause the spin cycle and turn the washer's cycle knob to the "Off" position. Turn the knob to "Spin Only" and press "Start/Pause" to reset the cycle.
3 Turn the wrench counterclockwise or clockwise around the unit's legs to adjust the appliance's balance. The legs are adjustable with the help of a wrench to ensure the unit does not shake while in use. An unleveled unit shakes as it spins, and causes excessive squealing or rattling as it attempts to dry the clothes.
4 Touch "Start/Pause" on the front of the washer's control panel and unplug the washer/dryer unit's power cord from the electric oultlet. Wait two minutes and plug the power cord back into the electric outlet. Push "Start/Pause" to resume the spin cycle.
Thanks.