I've been doing a bunch of looking on here for what gears to buy and still can't decide.

I've got a 2010 3.8l automatic with 35inch duratracs, 3.5 inch lift, smittybilt stinger, poison spyder rocker knockers, ace pro series rear bumper ect . I live on the eastern shore of Maryland so it's pretty flat. I daily drive my jeep but I do play off road. I plan on trips to Rousch creek and other places on the east coast.

What would you guys recommend. I know either would be better then factory but if I'm spending the money I figured it would be best to ask and be happy

 

I'm happy with my 4.88s but I have a manual.

 

I can't say for sure and I don't like to give false info without first hand experience but from everything I've gathered and all the PM's back and fourth with other members it seems as though 5.13's is the way to go with a 3.8 auto. I ordered a set of G2's with OH kits which should be set to ship any day now and I can't wait to get them on. A local 4x4 shop I spoke to claimed that all his 5.13 gear installs ended up with broken gears because the pinion is just too small and he strongly recommended 4.88's. I think it's the Dana 30 which is more susceptible to gear damage but regardless, I don't wheel my Jeep so I'm not concerned with blowing the gears and I'm aware that the pinion will be weaker due to size so I won't be spinning my tires or doing anything stupid. My biggest concern is higher RPM's at cruising speed but I too have 35" Duratracs, so 5.13's should put me right in the sweet spot for power and economy.
I'd say the majority of posts I've read of those going to 4.88 instead of 5.13 (automatic JK's) have regrets. All the posts I read of those going to 5.13 are happy with their choice. In comparison, the majority of guys running 4.88 on a manual (5.13 equivalent on an auto) are happy with their choice too. 5.13 seems to be the way to go and I'm sure that's what most here will recommend
Good luck

 

I run 5.13s and wouldn't want it any other way. 35s, auto and 3.8

 

I run 5.13's in my 07 JKU auto with 35' 1250 mud grapplers, they are about kicked so I'm making the jump to 37's. That is the beauty of the 5.13's they give you the room to go up in tire. I've been averaging right at 13.9 mpg's collectively w/o a programmer.

 

If your mainly concerned with hwy rpm, you could run with OD off. That would give you the feel of the 5.13's, more so towards 5.38 if your running 3.73 now.
There is roughly a 150-200 rpm increase with the gear sets...example 2300 / 4.88 2450 / 5.13

 

Sounds like you have been doing some research, so in all of the other threads, which of those ratios had the highest percentage of people endorsing it? (people with a 3.8 auto - not a manual, and not a 3.6). I'd bet the recommendation was 5.13's, and by a fairly large margin, correct?

See if you can find someone local with a similar setup that will let you drive it, or at least take you for a ride.

Or if nothing else, start plugging numbers into the chart in the faq's to see where you'll be, (divide by .69 to get OD Off rpms), then go for a drive and turn off your OD to get the rpms up into that same range. Should be close enough to get a decent impression.

For what it's worth, I started with 5.13's, then went on to 5.38's when the front axle was replaced.

 

yes it seemed like most ppl on the forums went 5.13. Then I've been talking to some ppl who think 4.88's enough. One of my friends is doing the 5.13's now. And my buddy just had smash boogie 4x4 install 4.88's but his jeep is supercharged so idk if that would give me a fair feel for them

 

I've got 4.88's with my 32.5's and my roof rack. If I had 35's I'd be 100% getting 5.13's, no regrets. 4.88's are great with my jeep now, if I get a 33 inch tire, I'll still be happy.

 

I'm very happy with my 4.88's on 35's, but I have a manual. Running at about 2800 rpm at 70 mph. Off-road, I can use 4H again.