my 03 fx4 screw has the B6 axle code which is 3.73LS rear end....how does this setup compare mileage or pulling vs other gears? just curious what you guys think of it! thanks in advance!

 

Well you can look at it this way. The taller the gear the higher your rpm's will be at highway speed. So if you are comparing 3:73's to 4:56 then obviously you will get better mileage at 65-70 with the 3:73's. But on the other hand if you put two of the same trucks pulling the same trailer, and one has 3:73's and the other 4:56's then the 4:56 will out-pull the 3:73's all day. Its just a matter of what you need. You will notice that most duallys will have 4:10's fresh off the floor. Its because you normally dont drive a dually with the intention of flying down the highway at 120mph. They are made to pull and to work, and the hardest part is getting that big trailer back there going.. do you see where I am going with this?