sutphinboyy

Hello Everyone, I own a 2023 Silverado 1500 LT 5.3 and I have changed the wheels from the stock 18in premium wheels that came on my truck to 35 x 12.50s. I am aware that my speedometer is off calibration reading about 5mph slower than it is actually going. IE actual 55mph displays as 50mph. That is not of the biggest concern, but my biggest concern is that the shift points are off and my trucks RPM is consistently in the 2000 - 3000RPM range even going from 54 to 55mph with the cruise control on dictates a gain of about 1000 RPM. I have purchased the Rough Country speedometer calibration tuner, which American Trucks states is compatible with my 1500 Silverado but the truth is that it is not compatible (verified with Rough Country) and they took the return fine. But my question is, is there anything that I can get that will work to correct my shift points and the speedometer both? The main concern is the shift points. I appreciate the help!