I went online to YouTube and searched for this particular problem and found a few videos dealing with this exact problem.
The video diagnosed the problem correctly. The 'dogs' in the device inside the agitator that prevents the agitator from turning in both directions were worn out and needed to be replaced. I searched the Internet for the part to fix my machine using the make and model number from my washing machine. I went to the Appliance Parts Pros website. Find the part was easy as they had and en 'exploded' view of the different sections of my washing and it was easy to scroll down and find the picture that fixed my machine. I input the model number and the website determined the correct part for my machine. I not only ordered the dogs but I also ordered the entire assembly that held the dogs. I considered it preventative maintenance. The dogs were ~$ and the entire assembly which included the dogs was ~$. The website indicated the order would be shipped on that Monday as it was the weekend. Low and behold, the order arrived on Monday. I followed the instructions from the YouTube video and the replacement was real easy. The toughest part was unscrewing the bolt that holds the agitator to the washing machine. It requires a little muscle behind it. It's working great!