Just to give light from the other side of the 6.4 spectrum... I had one for a couple years and absolutely loved it and never had an issue but it only had 80k or so when it had to go. Best towing truck I’ve had to date, and I’ve had a 6.0, 6.4 ,and a 6.7 powerstroke, along with 3 5.9’s and 2 6.7...