Automatic transmissions: Fluid and filter changes (BMW "Lifetime fluids" are not really lifetime-change every 50-60K). If needed, the following could make your transmission shift like new again: Valve body Mechatronics replacement. Valve body seals replacement (6 needed on several models). Solenoid sets replacement. Torque converter replacement. Transmission replacement with low mile options.
DCT 7 speed "dual clutch" transmission: Fluid and both filters change. Transfer case: Fluid change. AWD actuator replacement. Transfer case replacement.