Kenmore Elite top loader makes loud knocking sound when spinning

I have a kenmore elite oasis top load washer model number 110 27087602 model. During the spin cycle the washer will knock so hard it moves the machine out of position on the floor and will shut the machine down. I can reset it to spin cycle only only. Sometimes it will spin all the way through other times it will not. This is frustrating and I only had this machine for almost two years. It appears that the tub is out of balance or a spring is broken I can see through the glass top because it wobbles from side to side which causes the loud knocking sound. Thanks hope some one knows how to fix this problem I don't want to spend another $1000