I can't get in or out of bed without shaking my trailer! But then, I don't have any kind of pin box support or any additional bracing on the landing gear.
Do you have a 6 point leveling system? If not, then keep in mind that the whole trailer is resting on leaf springs, the electric rear stabilizers help a great deal, but not enough to counter an agitating washer. I don't know how much you washer shakes compared to others, but you'll want to brace up the pin box if you haven't already.