My son has an Alfa Romeo with the 8-speed ZF 8HP transmission. It has the same valve body as our trucks. (I'm sure some gears/clutches are different. At least, I'd like to think so.)
Anyway, the pan/filter is identical to ours. I bought a BMW-spec pan for ~$120 and Liqui-Moly brand ZF approved fluid (TopTec 1800 Synthetic ATF) for ~$80 (double the volume of fluid I ended up needing). So, all in ~$200 for a filter swap and a fluid drain/refill. (And enough fluid leftover for a second drain/fill.)
Here's the LiquiMoly link:
Top Tec ATF 1800
(That link shows their (inflated) MSRP of $27 a liter. That's wrong! FCP Euro sells it for less than $9 a liter.)
The pan
IS a ZF pan. Not a knock-off or off-brand. It is manufactured by ZF, but marketed for a BMW. (Maybe a 3 series?)
BMW-spec pan because it had the cheapest cost of a pan/filter for the same ZF valve body. When I pulled my son's pan off and compared it to the new one, they were identical: same bolts, gasket, internal baffles, magnet numbers and placement, and filter.
The biggest hassle is the temperature requirements for the fill. It's probably not really necessary, but they spec a fill temp range. Don't quote me, but I think it's like 140-145F up to the bottom of the fill hole. (Fluids change volume with temperature. I have no idea what the coefficient of expansion is for this ATF, but since it's under warranty, I'll do it how they say. Someone heated some up and showed the difference. Hmmm....something to do on the stovetop next week...)
A drain and fill only gets about 1/2 the fluid. I'll drain and fill my truck twice at each 40k with a single pan/filter swap. (1/2 twice means 3/4 fresh fluid.)