Yeah, its blown.
Sorry, but changing ATF won't rebuild it.
If you're lucky, it could be a solenoid(or other electrical issue) or dirty varnished VB.
Excessive line pressure, excessive idle RPM, hung up PSI regulator,..... are some causes.
If you're really lucky, maybe the tranny isn't slamming. Maybe your entire drivetrain is shifting/banging on broken mounts.
What the mileage and maintenance history on your transmission?