Hey, I see this is an old thread. I was just reading it and think I got a little confused. I currently have a 2007 Silverado(new body style). I installed 4.56 rear gear with 36" tires (375/65R16- so actually 35.2"). I am having the issue where the ABS light and Brake light come on. I can mess with the numbers in HPT to make it where the ABS doesn't come on but it ends up making the speedo to be off. Is there a way to make both the speedo correct and keep the ABS lights off with HPT or does the ABS module need to be reprogrammed from GM? I actually took the truck to our local Chevy Dealer and they had to call GM because the Tech II would not let them reprogram the ABS on this 2007 Silverado(new body style). So they call GM and told GM that they need a program for the ABS module for the listed tire size and they said they do not support that tire size. So if anyone can give me a point in the way to get this fixed that would be awesome. Thank you very much.