Washing Machine Defective Pressure Sensor?

First, make sure after the washer has finished the agitation cycles that it drains all the water first before the motor pauses and then begins to spin. If it's attempting to spin with a full tub of water it will eventually cause the clutch bands to wear out sooner than normal. The result could cause a lack of torque and friction to release the brake on the basket drive and begin spinning. Based on your symptom, the clutch will likely need to be replaced. 

In order to remove and replace the clutch, the agitator must be taken out, the washer cabinet must be taken off, remove the drain pump and motor and the gear case. 

First, 

disconnect the power cord from the power source. 

Pry the agitator cap off and remove the bolt located down inside the agitator. 

Lift the agitator off. 

Remove the left and right side end cap covers (key#14 and 11) and remove the screws at the bottom of both end caps. 

Slide the console towards the front of the washer, lift it up and hinge it over the rear panel. 

Pry the two gold colored cabinet clips off from the top of the washer. 

Disconnect the three wire lid switch harness plug from the top of the washer. 

Tilt the top of the washer cabinet towards the front and walk the cabinet straight out from the base and set it out of the way. 

Pry the pump clips off and slide the pump off the motor and pivot the pump (leaving hoses attached) over to the left side of the motor. 

Remove the motor mounting clips by prying them off (if a screw is threaded through the clips, remove the screws first). 

Disconnect the motor harness connector and remove the motor. 

Lean the washer up against the wall and remove the three gear case bolts. 

Pull the gear case down and remove it from under the washer. 

The clutch will be sitting on top of the gear case. 

You should not have to remove the basket drive shaft. When the clutch torques and spins around it strikes the clutch engagement cam which causes the brake pads to come in and release so that the clutch can spin the basket drive shaft and basket. 

Reverse the procedure to reassemble your washer. See images below. The clutch lining and spring is part #285790 which is available at 

Sears Parts Direct