Not sure about the newer V10 transmissions but my 99 V10 trans did not upshift or downshift very well.(my opinion) I bought a Banks Transcommand and installed it myself.It was about a 2 hour job.I am VERY satisfied with the trans performance now and that was almost 10 years ago.I was told by a Ford trans engineer it would extend the life of my trans.I have 80k miles on it now,towing a trailer most of the time and no issues.I use synthetic fluid and the trans never runs hot.