BMW’s recommendations are different depending on the year. For example, a 2001 model was a lifetime fill, but a 2002 with the same transmission and fluid was serviced every 100k miles.
Over the years, BMW has set various service intervals for automatic transmission fluid. 1995 and older models required service every 40k, but 1996 through 2001 were not serviced and considered lifetime fill. However, from 2002, BMW recommended service every 100k, but with the introduction of their F series (beginning with some 2011 models), they reverted back to the lifetime fill again.
Since these recommendations are inconsistent, we’ve consulted ZF, who manufactures the majority of BMW transmissions, and they recommend changing both the automatic transmission fluid and the filter every 50k-75k miles. Even though their transmissions are filled with ZF manufactured semi-synthetic oil, certain driving conditions will cause the oil to age faster.
So if your long-term goal is to keep the car beyond its warranty period, then we recommend servicing your automatic transmission every 60k miles.