So I have a 85 Chevy K10 with 35in tires and the speedo was close to acurate. Well recently I regeared the axels to 4.10 from a 3.08 and now the speedo is way off and says I'm going faster than what I really am. I guess the speedo was calibrated for 35s and 3.08 and not 35s and 4.10s. So how do I make the speedo accurate again? I know it has to do with the little gears on the tailshaft of the t-case. But what do I do to with them? BTW it is mechanical speedometer with the full cable n' such.