Maybe responsible is a poor word choice. ZF designed and built the 8 speed as well for many other vehicles. They also have top of the line facility and have the tools and knowledge as well as parts to do any repairs, maintenace like flushes and have the atf that it was specifically designed for.
Chrysler Group LLC initially received the 8HP 8-speed automatic transmissions from the ZF plant in Saarbrücken, Germany. By 2013, in parallel with Chrysler Group, ZF had set up a new transmission production plant in Gray Court, South Carolina. ZF Friedrichshafen and Chrysler Group have reached a supply and license agreement for the 8HP
I don't like quoting them but for speeds sake it will do