4:10 -vs - 3:73
 

Changing rear axle from 3:73 to 4:10 in a 2011 2500HD Silveraldo 2 wheel drive for towing purposes what are the pitfalls ahead and what else would have to be done to do this.

Inaccurate speedometer, lower gas mileage, faster shift points, lower top speed. Other than that, just replace your fluid with nice high quality stuff from GM, put on a new gasket and make sure to shim it up properly.

You actually get better gas mileage in town at least, more torque, power transfer should be easier on the tranny, a computer adjustment and you're good to go!

Why would you need to shim the rear end if you change the fluid?

You don't have to shim if you change oil. If you change gears they will have to be set.

I assume that you have the gas engine where the lower gearing can help as this engine develops peak HP at 3400 RPM. It would not be a good move with the diesel engine which develops maximum torque at 1600 RPM.

With the 6-speed transmission and the 4.11 gearing you do have the option of manually shifting into 5th and 6th overdrive gears to help the gas mileage once you get the entire rig up to highway speeds.

What and how much weight will you be towing, and how often?