When hard parts are replaced inside the transmission.This article should apply to any E-series vehicle that uses the ZF 6-Speed “Steptronic” Automatic. The ZF 6-speed automatic used in many E90-based vehicles like the 335i, X1, and 135i (among others) is an expensive transmission, and fluid replacement w/adaptation reset can be a great way to extend the life of it. When hard parts are replaced in a transmission or the fluid is changed, resetting the transmission’s adaptations may become necessary to restore shift quality. Unfortunately, a fluid and filter change is not as easy as it used to be. Throw in the fact that it’s a BMW, and the need for regular maintenance becomes quite clear. Automatic transmissions are fickle beasts which can be astronomically expensive if not maintained.
