An automatic transmission for a vehicle drivetrain includes a transmission housing, an input shaft, an output shaft, and a plurality of gears within the transmission housing. The plurality of gears defines multiple mechanical gear ratios between the input shaft and the output shaft. The transmission further includes a plurality of clutches operable to selectively engage the multiple mechanical gear ratios, and a plurality of rotational speed sensors. Each rotational speed sensor is operable to measure rotational speeds relative to the transmission housing for of one of the input shaft, the output shaft, or one of the plurality of gears. The transmission further includes a transmission control system configured to receive signals representing the measured rotational speeds from the plurality of rotational speed sensors and control the plurality of clutches to change between gear ratios based at least in part on the signals representing the measured rotational speeds.