if you pre load clutch load they hold up just fine for soft street tire cars. still have the same ford 4 spider unit been under all my cars never been rebuilt that.s has been over 27 years.i never busted second gear sprag in a 400 from letting off and getting back on the car and hitting second gear you can with a locker done it.to much roll out or engagement that.s the pop and click and hard on auto trans sprags if you making abit of power in a heavy car