Just had to double check but yes the zf8 is a sealed transmission. No service for normal driving. If you drive it very hard you CAN have it flushed by a dealer after some years but it is a more complicated process. Most new transmissions are sealed fyi.
the filter and pan are one part that is a throw away and replace. then refill. They call it lifetime maintenance free, but no one ever defines lifetime, I know people who have not changed theirs in their cars for nearly that long without issue. BMW says its 100,000 miles, no one really knows what Chrysler says it is. but between 60-100k is a good plan depending on how hard you are on it.