i heard a “POP”

i was stalling my 440/727 @ a redlight & then i heard a pop. i was only stalling at 2K.

the car is equipped w/ a $600 3800 stall converter & a $1000 reverse pattern 727. the car only has 6 passes on it so why did something go wrong?

the car drove back home but it doesnt feel the same. it has a "rough" feel to it where it was smooth before

what could of happened? this is kinda hard to explain

i just changed the fluid a week ago with B&M fluid and a brass trans filter