[wolfrace]

I have been unhappy with my shift points in low speed hill terrain (lugging), a while ago I changed my tire size in AE, I was wondering if this will change my shift points? on another note I have 37" tire I tryed that and it made my speedo go from to slow to much to fast? I think I am around 33" and speedo is still off (speedo show faster than actual)

[cleatus12r]

Changing the tire size using AE only changes the tire size parameter in the ABS module and doesn't do anything to correct shift speeds (which are controlled by the PCM). As you have found out, the ABS module change only makes the speedometer accurate (or less accurate depending on how far you go).

There are a couple of ways to change the shift points, but they all involve reprogramming of the calibrations on the chip to accomplish this goal.

Changing the tire size does not change the shift points either by measured speed (from the speedometer) or by RPM. It simply changes the actual ground speed at which the shift points take place.....which just happens to be a lowered ground speed. With the change in the absolute final drive by changing the tires, the truck effectively shifts at a lower point, making the truck feel sluggish or that it is bogging, when in actuality, the PCM thinks that it is shifting at the right time based on it's programming.

Since you have the FU, there aren't any changes we can make to your programming because everyone that uses the VRAA6S3 calibration you are using (which number in the hundreds) would have shift points that become too high with their stock-ish tire sizes.