The pdf file generated an xml error and would not load. The mopar/snapon link doesn't go directly to the part so I'm not sure if this, <www.moparessentialtools.com/item-detail.aspx?itemid=30470017&type=tools> is the right part.The gearbox it is the same 948TE, a modified version of ZF 9HP, used in Jeep Cherokee, Ram Promaster City, ...
Maybe You can find some answer to your questions in this PDF document
For checking fluid level You need a special dipstick. Yopu can find, for example, at "MOPAR ESSENTIAL TOOLS AND SERVICE EQUIPMENT" (https://mopar.snapon.com/)
in ZF 9HP an optional cooler can be attached directly to the gearbox housing.
I've got 106K on my 2015 Trailhawk and I'd like to see about changing that fluid. I was sent the PDF file for changing the filter/fluid. They show the entire transmission having to be removed. Surely there's another way using the dipstick took and dropping the pan?