news to me lol thats a false statement.
now overkills trans tune can kill a tranny fast, i know of a few guys who's trannys let go from it. i dont have that tune.
shift kit up line pressure, makes the trans shift faster and firmer, making the trand last longer if driven like a normal person, aka not beating the tar out of it daily.
trans tune can make the tc lock up sooner at light throttle make it shift at higher shift points. up the line pressure more if you want to. theres a bunch that can be done.
a lot of us are rocking the billboost trans tune. we all love it. ( those of use with a tuner that is )