OOPS! I failed to mention in my question that the worn places on the sway bar were on each side of the sway bar isolation bushing.
I had new motor mounts installed about four months ago and the problem was fixed, however, I now have the same problem or one very similar. I carried the van back to the shop that did the work and he checked it out and said it was not the mounts and to bring it back later and he would see if he could find the problem. I wanted a second opinion so I carried it to another shop. He checked it and said it was not the mounts and to make an appointment to bring it back and he would see if he could find the problem. At this time I decided to call on the smart people at Driverside to get some idea so I would know how to talk to a shop about this problem.