15+ Dodge Gear Ratio Change

Very disappointed that even after the update today there's no way to configure the pcm to accept gear ratio changes. I have a 16 Charger RT which I upgraded the rear differential to a 3.90 lsd. I get trouble codes for transmission output shaft overspeed and another I can't remember at the moment. It would sure be nice to be able to configure ratios in the normal user interface.

[mikel]

Well, we've never offered it as its never been necessary for any 8 speed that we have seen?
Is the speedometer incorrect with the gears installed?

Speedometer is correct but the transmission doesn't select an appropriate gear during downshifting because of the transmission speed.