I've had the S55 almost two weeks now. They did the reflashes. They've done reflashes before, so it all seemed routine. I can't tell if its my imagination or if its more tangible, but after every reflash they've performed, the tranny always seems to be smoother. I've never experienced the many issues noted by others on this forum, so there never has been any drastic changes. I do think that it is smoother since S55.
2015 Cherokee Trailhawk:
Granite Crystal, 3.2L V6, 8.4 Nav, black leather, sunroof, tow, tech, comfort/conv, no hood decal, 9 speakers, CD player, Maximum Care lifetime warranty, Mopar first aid kit, rear rubber cargo mat, Thule Aeroblade cross bars (black), Thule Rapid Aero feet, Kuat Vagabond X cargo basket, RRO rock rails with smooth covers, Mopar door sills, Raingler ceiling net, Raingler seat headrest handles, MFC aluminum lift kit, RRO winch bar and Warn M8000S winch, BFG T/A KO2s