I have owned this van since '96 and had the tranny rebuilt at 83,000. It now has 206,000 on it. About 2 months ago I drove from here in PA toConnecticut which was mostly highway. On the trip home I noticed a shimmy which was not bad but noticeable at around 60 MPH. I had the tires checked and balanced in case I had thrown a wheel weight or had a failing tire. The tech told me the tires were fine and balance was off by .5 gram on the left front. On the ride home it seemed exactly the same. It's been 2 months and it has gotten so bad that it feels like your teeth are going to fall out when pulling even a small hill at 40 MPH. AT 40 MPH, the shaking is at it's worst and it's important to note that this shaking only happens when you are on the gas. The rythm of the shake makes you think you have a tire where the tread is delaminating if you've ever felt that. But let her coast and the shaking is gone immediately - at any speed. There is no CV clicking on corners or straight. Looking under I see no torn boots or anything else obvious. Help! I'm really at a loss here.