Attention: TDR Forum Junkies 
I installed Superlift's True Speed Speedometer calibration unit last night on my truck and it is AWESOME!! I have 3. 54 gears and 315 BFG's. My transmission was confused, the TC would lock early and in city traffic it would kick in and out as I hovered around the speed where it wasn't sure what to do. The speedo and the odometer were off so I could never REALLY tell how my mileage was. This unit brought everything back into spec and was a breeze to install.
I calibrated it my own way. The instructions come with a chart that says to go so many turns for a certain percentage. I had a friend of mine put the cruise dead on 60 MPH as I rode shotgun with a GPS unit. By adjusting the True Speed unit with the cruise control on, I was able to control the speed of the truck from the unit. I adjusted the True Speed until the GPS matched the 60 MPH that the truck thought it was doing the whole time.
This is an exceptional unit that would recommend to anyone running larger tires, especially with the high gears I have and an auto transmission. I paid $175. 00 from Summit Racing
Next I need 4. 10 gears to get me out of the hole faster. At least I know I can adjust my speedo with ease.
I calibrated it my own way. The instructions come with a chart that says to go so many turns for a certain percentage. I had a friend of mine put the cruise dead on 60 MPH as I rode shotgun with a GPS unit. By adjusting the True Speed unit with the cruise control on, I was able to control the speed of the truck from the unit. I adjusted the True Speed until the GPS matched the 60 MPH that the truck thought it was doing the whole time.
This is an exceptional unit that would recommend to anyone running larger tires, especially with the high gears I have and an auto transmission. I paid $175. 00 from Summit Racing
Next I need 4. 10 gears to get me out of the hole faster. At least I know I can adjust my speedo with ease.
