Agitator will not rotate

The washer did not Agitate although it did spin. So the motor appeared to be good. I noticed that you could rotate the agitator by hand, that didn't seem right. So I pulled the Agitator off the coupler. Now the coupler can rotate by hand around the spline shaft. I removed the bolt holding the coupler to the spline shaft. The spline shaft looked good. Ordered the new couple and installed it in 10 minutes. I was fortunate that the bolt came off easy. I didn't need to use the motor to assist in getting the bolt free.