Gear Ratio Adjustments

[Bonjoyle_70]

If anyone out there knows the answer to this I would sure appreciate a heads up...I have purchased and installed a fully customizable tranny in my 2010 Sti and when I go into "Tuning" from "My Garage", the only option the game allows me to change is the Top Speed...What Gives? In GT4 I was able to tweak each gear to stop slippage due to boost when accelerating off the line.