Installing the AO4D internals does not give you the overdrive of an AO4D, it lowers 1st and 2nd gear to give you more power in those gears. You will still retain the 1:1 ratio in drive. The way it waexplained in the article I read, if you're currently running 4:10 gears on 33's, in 1st or 2nd, you would have the same gearing as running 4:56's on 33's.