No additive will affect the spin cycle, only oil leaking on clutch, or over loading, and some say spin brakes dragging will do the same, to make the tub run slow.
but there's one thing that might be wrong with your machine, the spin basket drive block might have broken, if so it lets the spin basket slide down and rub the bottom of the tub and do what you say. I've only seen this 3-4 times a year, but acks like what you say. To check remove the agitator, and see if the shiney 1 inch round spin tube is sticking up from center post about 1 inch from being normally flush from block and large ring nut, the spin basket will be dragging the bottom of the plastic tub If so do not operate untill you change the drive block and ring nut.
Good luck |