I own a 2007 Tahoe w/ 214k miles on it. My rear dif started making a loud noise so i took it to the dealer and they said i needed to replace the ring n pinion. Since I tow quite a bit, I opted to change from the stock 3:73 to 4:10. Truck runs great but speedo is now not calibrated properly. I tried to do it with an after market tuner but it did not work. I took it back to the dealer and they can't re-calibrate it because it's not the factory installed unit. I went with the 4:10 because chevy offered it as an option for this truck. Any advice will be greatly appreciated. Thanks in advance.