It’s currently got the factory 3.73 gears in the differentials but after a routine check the other day it was discovered that the popping noise I hear during acceleration was not the u-joints but it is the rear ring and pinion gears wearing out. I currently have a 4″ pro comp lift on my TJ and it’s got 33×10.5 KM2′s. The tires only have 6,500 miles on them but I already know that when they are worn down I am going to go up to 35×12.5 tires, probably KM2′s again. I put a lot of miles on my Jeep so the new tires aren’t many years away, probably about a year and a half. I’ve only had the Wrangler for 21 months and I’ve run it up from 77,000 miles to 116,000 miles after all.
Anyways back on track. I was thinking that because I am going to go up to 35′s in the not-so-distant future, I should probably go ahead and put the gears in that will work best with those instead of the best for the 33″ tires. Yes I know my gas mileage will be worse but it will have more power too for the time being. Would 4.56 be a good choice? It is my daily driver so I don’t want to go crazy with the low end power but lose top end speed, a lot of my driving is on the highway. That is a bit of a problem I am experiencing right now is that I get 11 mpg with the 3.73 gears because on the highway I have to down shift to 4th just to maintain a speed above 65 going up any kind of hill or into any breeze. It has the 4.0L engine too.