Appliance repairmen help!

It is a really easy job to replace the motor coupler. Unplug the machine and disconnect the washer hoses and drain line. Tip the machine over (get the water out 1st) and the drain pump, motor and transmission assembly should be visible. un clip the drain pump and then remove the bolts that hold in the motor. The bolts should screw in right handed and loosen left. Then separate the motor and coupler from the transmission. If the coupler is at fault then you should be able to put your hand on the coupler while the machine is still all together and while holding one end of the plastic coupler, try to turn the other end of the coupler. If it does not turn all at once (both ends of the coupler together) then the coupler is more than likely the culprit.
It could also just be the drain pump itself. remove it and check for obstructions or blockages, you should be able to insert a wide flat bladed screwdriver into the hole that the pump attaches to the shaft and spin the pump. if the pump does not turn it is the drain pump.
It could also be the lid switch, If the timer will only advance to a certain point in the cycle and the machine will not drain then replace the lid switch.