DIAGNOSIS The suspension system is compromised. Either the shock absorbers have lost their damping fluid or the suspension rods/springs are broken.
FIX Tip the machine back (get help, it's heavy). Inspect the two shock absorbers attached to the bottom of the outer tub. Check if the piston moves freely without resistance. If they're loose or oil is leaking, replace them (part #WPW10704138). Also check the springs at the top of the tub for detachment.
IF THAT DIDN'T WORK The concrete counterweight mounted on the outer tub may have cracked or come loose. This is less common but causes extreme imbalance. You'll see cracks in the concrete block if you remove the top and front panels.
HEADS UP Always use all four shipping bolts to transport the machine. Operating it even once without removing the bolts will destroy the suspension system and likely the outer tub.