Torque and Chrome

1999 GMC SIERRA REAR END ISSUES?

Do i need to replace my trucks rear end ? 1999 gmc sierra, i have replaced the factory tires and wheels with some aftermarket 22 inch chrome wheels and low profile tires. I just had transmission rebuilt about 6 to 8 months ago, also replaced the spider gears in the rear end, but seems to be having issues again. Someone told me that i needed to swap out the rear end with lower a gear ratio when i put new wheels on it. The gear ratio now is 3.42 , its the original rear end . The truck has 200k miles on it, but has been very well maintained. Should i have put in different rear end with lower gear ratio? Davids wife

Public Comments

1. Whats suppose to happen is,you get bigger wheels but the tire diameter or circumference stays the same as the original size,then you don't have to change the gear ratio. What does happen is,20 inch wheel and tire combos work out pretty close to original and 22's are too big. Your engine,trans.,and final gear ratio work together with the recommended tire size thats on the vehicle placard on the drivers door. When you go too far,bigger or smaller in tire circumference,it makes the engine run at different rpms. and the trans. shift points change from the normal. End result is using more gas,poor acceleration,less power.To fix,you need to change gear ratios.