This is normal for that tranny. It is more noticeable during the winter. Due to the gear train moving w/o being fully clutched. I have 178,000 miles on my 300E and it has done this since it was new. (11 years and counting).
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.