After 30 years of shifting, I absolutely love my 579 with an Eaton fuller automatic. I don't have any of the problems that you are describing. I drop it down into manual in the mountains and it's perfect. Sorry that you are having such a bad experience.
I bought a used 2020 579 Pete since May of 2023 it took me a while to get leased on with my company. Now it's time to go to work in it after the dealer warranty is off. OMG I worked the truck for about 3wks. Now having automatic transmission problems it's a problem on top. Fred
