My washer and dryer are installed as a stacked unit.

When new they were soooo quiet, but got noisier and off balance over time. Yesterday, I completely removed cleaned readjusted all leveling feet and locked tightly down when level in all directions. The machine still shakes under spin cycle it appears when I look underneath that the "case" is shaking on the foot. The foot never leaves the ground but the cabinet rocks? I tried to crank it downward applying more pressure up into the cabinet this does not seem corect and will likely take the unit off of level. Any tips? Am I doing something wrong?

Raised foundation, new ply, hardy backer and 14" ceramic tile the floor is pretty solid.

Chuck