The transmission on my 2013 Dodge Journey was shifting harsh between second and third gear. ( shifting too fast). I went to dealership and did the transmission service. They said they replaced 2.5 quarts of transmission fluid and the internal filter. I drove the auto for a month but still the gears were shifting too fast, like a gear slam. I decided to change the fluid again myself and used a pump and removed about 2 quarts of fluid. I drove the car a month, then did it again. So this is equivalent to about 4 quarts of transmission fluid change out. After one week the shifting improved considerably. After 4 months the vehicle shifts 90 percent better. I think the fluid change was all it needed. I wanted to do a fluid flush but decided to see how this 4 quart changeout did. New fluid did make a change. Getting 26.5 mpg on freeway, and engine running great. I purchased this Journey with 118,000 miles on it. The previous owner only did the required oil changes I was told. None of the other preventative maintenance was done. All the fluids were dark and worn out. I think Dodge should make it mandatory to change the PTU fluid, rear differential, and transmission at the recommended intervals in order to maintain any warranty. Most automobile owners have no clue how their engine operates and how important preventative maintenance is. My feeling is if you cannot locate your oil dip stick, your battery, and the drive belts, and know how to change a tire you should not be operating a powered vehicle.