Gear Ratio Change Problems

[jhall195]

I have an 09 Challenger RT, auto. Have downloaded the latest crom file and calid. I selected to load the 91 Octane w/CAI performance tune, but opted to modify it prior to install. I changed the gear ratio to 3:23, turned off the MDS, set tire size to 245X45X20, and increased shift firmness. After installing the tune, and test driving the car the transmission does not shift above 3rd gear and when stopping the transmission will not downshift at all. Even from a complete stop, the car takes off in 3rd. I know it's in third, because I stopped the car, turned off the ignition, restarted and after putting the car in drive selected manual shift mode and the highest it shifted into again was third, and again would not down shift and the indicator stayed in third gear starting from another complete stop. Am I selecting something that is conflicting with the tune? Any help would be appreciated.

Thanks

[Mike_Levy]

Do you actually have 3.23 gears in the car? Doesn't sound like it. Don't screw with the gear ratio unless you have changed the ring and pinion.

[jhall195]

No I haven't changed the ring and pinion. some one had told me that you could modify the ratios through the transmission computer without actually changing the gears. When driving the car with this changed though, I could tell a heck of a difference in the amount of "pull" it had from 1st through 3rd, just wouldn't shift out past that.... Changed it back to the original performance tune settings, and everything is back to normal. Thanks for your answer, I'll leave it alone in the future.

[Mike_Levy]

Whoever told you that should be avoided in the future for performance advise. Its not physically possible to modify a mechanical gearset through computers.

[jhall195]

Thanks for the advice! Well received and appreciated.