Q: transmission shifting rough

Hi there, thanks for writing in about your 2004 Cadillac DeVille. Hard shifting can be caused by several items. I don’t feel like the pickup screens are contributing to your concern. The transmission uses hydraulic pressure to control the shifts. It also used electronic controls to determine when and how quickly to shift gears. Check the vehicle for vacuum leaks, as this will make the computer think that you are accelerating harder than you are, and will command the transmission to be more aggressive. Have an expert fully test your unit for correct pressure or internal issues that could be contributing to your concern. If you would like to have this checked, a certified professional, such as one from YourMechanic, can come to your car’s location to diagnose your shifting issue and recommend the appropriate fix.