I just had the latest computer firmware update done at my dealer to fix the erratic shifting on my 4.8. After completion is does shift smoother but the ride feels firmer. I remember reading when the 4.8 came out that because of the full air suspension the parameters like ride firmness can be programmed into the updates. Anyone had any experience with this. All help is appreciated. I have rechecked the tire pressures & they are normal. Thanks.