I have a 3.8l jku automatic with 35’s, 3.25in lift and less then 60miles a day of highway driving. Also a lot of aftermarket mods which added weight, for example: Front and rear bumper and 9500 winch. Also i drive hard, not like some oldie. I do about 75-80 on the parkway and do not take 100yards to get up to the speed limit(while not jumping the light).
What do you suggest?
4.88’s
or
5.13’s

what is you mpg?

If you have 4.88 do u wish u went with 5.13's? And vise versa

 

I drive like an oldie :(

 

5.13 for your set up. I have 5.38 on a good day I get 15 mpg I also have 37s

I had 5.13 before but bounced up

 

5.13 would be what you will want. PM us if you would like a quote.

 

I have a 3in lift with 35s and have been driving on 4.88s for a few weeks. Just my opinion but its to much gear. I do about 10 city 10 hwy a day. Does great in city but hwy it's to much gear... When I'm above 65mph it revs to high, stays right above 3k at 70mph. At 75-80 even more rpms to keep up to speed. I do have the Superchips installed as well. I feel it will be much better with 37s. Seems one misconception about a gear change is like adding unfound hp... And it's not... The 3.8 is pitiful and no gear changes that. Just my opinion and experience. Many have different

 

Also I live in the east TN hills, and average 16mpg depending on how light I'm on the throttle

 

I went 4.56 for my smaller 315 duratracs and high speeds. It's working great for me, but for most I would say 4.88.

 

If I were you I would re-program ur superchip. May be the problem.

 

Granted I have a stick, but I couldn't imagine 5.13s with 35s. I have 37s and 5.13s and with my manual trans it's a bit much for highway speeds. It's a perfect ratio for me because mine is not a daily driver, so I like the benefit of the lower gears around town and off road. I ran 35s with 4.10 gears and thought it was a good fit. So that being said, with an auto I would think 4.88s would be a good fit too.

Another question to ask yourself. Are you going to be done with just 35s. If you plan to go 37s later on then go ahead and do the 5.13s.

 

JKU auto with short 35's. I pulled the 5.13's out and went to 5.38. Is it the right setup for you? No clue, but I'm sure happier with the new gears.

There must be a thousand different 'what gear' and 'what's your mpg' threads on this site. Read through a few and find some people with similar setups and locations and driving styles.