When the motor turns in the spin direction, the transmission pulley has a cam that it pushes up and this releases the brake that holds the tub in place during agitation. The early version had a bearing that would disintegrate.This changed the height of the stacked parts and the brake would not release. There is a kit to fix this problem. Part number 12002213
. Make sure there is nothing stuck between the tubs preventing the tub from spinning. And finally the transmission could be bad.