how much hp can my stock tranny take?

[ave8tors]

i have a 2008 with 6.4l with automatic, how much hp can i turn my tuner up with out hurting my stock tranny. thanks

[Chasin' Tail]

A lot of guys run the 300 and up tunes no problem, just have to drive with some sensibility.

[KRJustin]

What parts in the tranny would be the first to break with a big tune.

Im thinking about getting the kem345 tune, thats really the only thing that I worried about is how hard it'll be on the tranny.