To prevent damage occurring during transit, some washing machines are delivered with 'transit bolts' attached to the rear of the unit. If the four transit bolts are not removed from the machine prior to use, the machine may shake or vibrate heavily.
These are located in the rear of the machine as displayed below.
During spinning, transit bolts which are still in place may result in damage to both the machine and adjacent furniture or appliances.
Ensure all four transit bolts have been removed from your unit, and the holes plugged with the transit bolt caps provided. This will resolve the shaking issue.