Tuning for diff gears

[immortality]

Hi All,

Considering fitting some 3.45 diff gears in the VS (ecotec).

I did the same on my manual VN and just used a speedo corrector box to fix the dash speedo, however with the Auto (4l60e) I believe that I need to alter tune to suit.

Can somebody let me know what needs to be changed to make it all work without needing to fit a speedo corrector kit.

Edit:i'm using the CKUL bin

Cheers

[charlay86]

To do it without using a speedo corrector you would need to re-program the dash, I believe.
The shift points should be mostly fine since the VSS reads the tailshaft speed, not the final drive.
Although you may need to adjust them slightly since the motor can accelerate at an increased rate due to the altered diff ratio.