T&C Transmission & Steering Shudder

My 2004 Chrysler T&C V6 was shuddering when turning corners at low speed at all times including backing out of the garage in the morning.
Since it was under warranty I took it to my local dealer. The diagnosis (without a test drive) was it needed an oil cooler. I reminded them that it does this when the oil is cold! They insisted they were right. They are the trained mechanics so I said go for it!
The service person said that my transmission oil had to be changed (31,926 miles). I recalled 60,000 but he said he was sure about this. I have to mention that there were no transmission problems with this car. When driving the car home, the shift points were all screwed up. First to second was around 4k RPM, the transmission downshifted without warning, and clunked when shifting. I brought the van back immediately and asked him if he test drove the car; "wasn't necessary!"
He then told me the transmission has to "re-learn my driving habits" which will take about 50 miles. I have performed so many transmission oil/filter changes and never had this kind of problem. After 300 miles I brought the van back to the dealer because it improved but not as good as it was before. He said "give it a few hundred more miles." The van now has 41,192 miles. If I accelerate from a light then take my foot off the gas (traffic slows), the car shakes and I hear a clunk sound. There was nothing wrong with the trans before the oil/filter change.

The power steering oil cooler didn't fix the shudder problem and according to the manual, the transmission service interval is 60,000 miles.