It's a good chance the above answer is correct! Another possibility is that a small article of clothing has gone over the inner tub (wash basket) and is caught in the outlet flange of the outer tub, in the tub to pump hose or gone all the way into the pump to strip the impeller.
In fact I had a costumer yesterday that had washed a comforter which spit during the wash and dumped most of the fiber insulation into the tub, a lot of it finding it's way to the pump.
