trucks in sig. i have an axel code of 18, what gear ratio is this?and what are the pros and cons of going to 4.55. hmm the site i went to didn't have trans code of k listed?

 

18 is an open diff with 3.08 gears. K is the C-6.

 

You dont list what size tires you have but going to 4.56 with say 31's will give you a butt load more low end power but will make your motor run out on the highway. Your highway gas mileage will decrease as well. If you put larger tires on when you re-gear then the mileage should stay the same and you can go the same speed on the highway. I would suggest 4.10's for 33's and 4.56 for 35's.