A reverse clutch and planetary gear set are provided that can be installed in an automotive transmission. In some embodiments, the reverse clutch and planetary gear set are configured and dimensioned to be installed in a Powerglide transmission case. In other embodiments, the reverse clutch can have an increased mean diameter. In some embodiments, the reverse clutch can have an increased static holding capacity. In another embodiment, the planetary gear set can have a reduced numerical first gear ratio. In other embodiments, the planetary gear set can have components with increased strength. Methods for modifying a transmission to install a reverse clutch and planetary gear set are also provided.