Diagnosis
The suspension rods are worn out or the shipping bolts weren't removed. This model uses four spring-dampener assemblies (rods) that connect the tub to the corners of the outer cabinet. They absorb the wobble. When they lose tension, the tub can bounce around.
How to Fix It
Unplug and pull the machine out. Tip it back (get help) and look at the bottom. You'll see one end of each rod connected to the tub base with a nut. The other end hooks into the cabinet corner. They can be replaced individually. The part is often W11035679 for a rod kit. You'll need a socket to remove the bottom nut and a bit of wrestling to get the new rod's hook into the cabinet bracket.
If That Didn't Work
Make absolutely sure the three or four large bolts and spacers used for shipping transport are removed from the back of the cabinet. If they're still in, the tub is rigidly locked to the frame and will shake terribly.
Heads Up
Also check that the locknuts on the legs themselves are tight. The machine should be firm on the floor, not rocking. Use a wrench, not your hands, to adjust them.