Early September 2018 build, 2019 2wd 8 speed 5.3L, transmission temp never exceeded 170, now while driving same route and conditions the trans temp is 185 and the 1-2 + 2-3 light throttle shifts are slide/ bump affairs and the corresponding downshifts are very harsh. Started all of a sudden. Very repeatable. When the trans temp is below 175, it upshifts and downshifts fine. Warranty still in effect, fluid never updated to the newer Mobil 1 version.
Anyone have any experience similar to this? Thanks for any insight.