New Gears

[KJJosh]

Guys will i have to install 4:10 gears if I put 31 tall tires on? What about 30?

 

[ridenby]

No and No

 

[Porkchop]

Has to be reflahsed for speed and trans

 

[Idaho08KK]

I run 245/75R16s on my 08 KK. They are a 31" tire. I run the stock 3.73's with no problems at all.

 

[KJJosh]

If I dont have to put 4:10 in for a 30 or 31 tall tire. Why would someone have to replace the gears in there KJ????

 

[tommudd]

when you go bigger than 30s / 31s

 

[tjkj2002]

4.10's and "E" range 245/75's are a great combo.

 

[riptricket]

is it still a good idea... funding permitting... to upgrade to 4.10's? better mpg?

 

[incommando]

I honestly believe that 245/75's and a 6-speed are a good combo even with the 3.55 gears. The auto is a totally different animal though.

 

[jcbll95]

4.10's and "E" range 245/75's are a great combo.

Unless you have the 2.4L 4cyl and live in WV then they still arnet low enough

 

[f1paul]

u never have to.

woulld still be beneficial performance wisethough, akin to adding like 20-30 ftlbs torque, i would think.
trade off would be lower top speed, no biggie.

 

[J-Thompson]

Ran our KJ with 3.73's and 245/75 LR E's for 3+ years
no reflash or stuff like that and had no issues
mind you it was an early '03 with the 45rfe which has a lower 1st and reverse
gear than the 42rle you have
we got an average of about 17mpg with about 40/60 ,city/highway, driving
which was down from 19mpg with 225/75's
we would have NEVER made up the cost of regearing in fuel savings
That does not mean that I did not want the lower gearing but could not justify
dumping that kind of money into a rig we were getting rid of
Now my TJ is running 3.73's with 32's ,OD is closer to most 33's, and it ***** on road
even with the 3 speed auto first is just not low enough
how ever I want 4.56 or 4.88 for trails but I would be cranking out 4K rpm to do 60
so I can not regear it until I can tow it