I read up on some gear ratio change posts. i came across russ k's way to change the gearing. i have a 4t65ehd tranny from a gtp. changed to teh gmr 1" chain which is 35 teeth on driven and drive sprockets so the drive ratio is 1:1 for a final drive ratio of 3.29:1. now i left the 1.121 sprocket rario alone and inputed 3.69 because 3.69/1.121= 3.29 for the new gear and left the tire size alone. now im getting a improper gear ratio code. one one with some insite here.