Rough downshift at 30mph when decelerating. This happens when 'D' is selected on shifter. It does not do this at all, when '3' is selected on shifter. No codes are present. Fluid/filter were changed, correct fluid is used. Torque converter not unlocking? Any ideas? Thanks

 

Do you have a scanner that can read CVI reading? From what you are writing, it could be a bump stop as we called it in the old days or the 2/4 clutch may have a problem. But I won't know until I can see the CVI reading.