If anything, it is only a band aid and the problem will have to be resolved sooner or later. Once a leak starts, the only real fix is to replace the leaking seal or gasket.
Stop leak swells seals in your transmission, in turn taking up any gap in the seal. I Have never had luck with any of these stop leaks but in order to replace that seal the tranny must come out......so what the heck you don't have anything to lose if the stop leak does not work. and if your paying the labor to have the tranny removed, i would recommend getting a rebuilt/reman tranny. In my opinion its a lot of labor to pay just to have one seal replaced......
you can try it ,it wont hurt nothing ,but there's no guarantee that it will stop the leak in it,sometimes it will though ,but its only a temporary repair at best,most of the time its just a waste of money,good luck.