Chrysler 300m special is shifting hard and at the wrong time. Whats going on?

[BrittanyLow]

My car which is a 2003 chrysler 300m special, has been giving us difficulties. While driving it,it will shift hard at twenty kms and sometimes shift hard at 50 kms, then will shift hard always at seventy. It doesn't seem to shift at the right time example: shifting at 50 not 60, and shifting at 70 not 80. Anyone have a clue whats going on? They already did a transmission flush and reset our computer which seemed to work for a day then it starting shifting weird again!