highmileage

I happen to have come across a pair of low mile stock 3.55 axles. my stick has 3.07 gears, what can I expect my fuel mileage change to be if I put them on and what about RPM changes. with the 3.07s I am at 2100-2150 at 75 MPH.

volaredon

I'm curious too; with 235/75R15s and 3.07s 5th is about useless in my TJ. it was worse useless, when I had the 31s on it.

zak873

anywhere from 1-3 mpg increase I would say. talk about 3.07's sucking *** with 31's, try 33's

Metmknice

http://www.grimmjeeper.com/gears.html

DO it, you will not regret it at all.

highmileage

Cool gonna get it done,thanks.

NorCalJeep

why didn't they put 3.55s in 5spd in the first place?

captainofiron

thats exactly what I am thinking, because almost every other manufacturer puts lower ratios into vehicles with manual transmissions

highmileage

I think it's because 3.55s would turn first into a granny low type of gearing. From what I understand the 5 speeds case or internals cant take the torque. H*** most people that bought cherokee's in the first place back then were "yuppies" and had no idea what what a grannny gear was, and would have probably grenaded their tranny. Or I could be wrong and it was an emissions thing. (sorry if I offend anyone with the "yuppie" comment)