Speed is $...

Dont happen very often but maybe twice in this thread.A slipping sprag in the converter,will turn a tork multiplyer into a fluid coupling.What appears to be stall speed,is not making any tork it’s just beating the oil to death.It can be hard for a layman to diagnose. A decent tranny guy will pick it up easily .If your tune checks out it may be worth your time to have it checked out.