Two different ways to do this based on what we have seen with the factory ZF fluids. Either change it at 30,000 miles by simply doing a pan drain and then refill and take the fluid out another 35,000-40,000 more miles and then change it at 70k miles with the filtran pan at that point pushing it to the limit of the filter.
Or just drive to 50,000 miles and change it along with the filtran at that time. The fluid comes out black and gritty at 50k miles and there is no way that I would recommend going 100,000 miles on this fluid!
If the vehicle is under warranty then we recommend an OEM Chrysler pan which we provide at 10% over cost and include the QuantumBlue ZF 8 Speed Replacement Racing ATF at $14.95 per quart and $119.60 for 2 gallons.
Remember that the 8HP70 filtran is $307.00 from the dealership as of today and their fluid is $33.50 to $43.25 per quart.
Here is more information on it but you really have two choices to protect this unit:
https://www.chargerforums.com/forums...d.php?t=303257
For reference, this is what ZF recommends: