[KhanTyranitar]

Also, you should have checked here before getting a powerflush. Its ok, in fact recommend to do a complete fluid changeout, an method that has been posted here as a sticky, but any flush that uses outside power to push the old fluid out is a big no-no, especially if they don't remove the pan and change the filter first.

And yes, that is true, but your issue is with OD not holding, which tells me that something else is going on here.

You are probably going to need at least a valve body rebuild if not a full trans overhaul.