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working on buying a 10a jkur and I will be going with 3.5" lift and 37's immediately, but I cant decide between 4.88 and 5.13 gears. jeep will see a lot of road use (~60 miles round trip to work) and some of that will be flat towing my tj around, it will also see a decent amount of trail use. I keep thinking 5.13's but im afraid that is too deep for highway use all the time, what do yall think?
 

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I just finished my JKU build and went with 4.88 and 37's tires. The jeep has more get up with the 37's and 4.88's then it did with stock tires and 3.73's. Runs about 2450 RPM at 70 on the highway...

I think 4.88's and 37's is a prefect combo!!!
 

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Manual or auto?


Mine is an auto and I have 4.88's. My tires actually measure at 36 and at 70 mph I'm around 2700 RPM. So I'm glad I went 4.88.

Not sure how high I'll be when driving out of town. With 85 MPH speed limits, it'll be screaming. LOL!


Sent from a payphone
 

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On my 2015 JKU with 37" Nittos I run 4.88 and as mentioned above, it feels like the Jeep has more get up and go now then when it was stock
 

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Discussion Starter #7
I think that's the plan Marcus, I was thinking 5.13's but with so many people saying 4.88 I guess that's gonna be what I do. As soon I get the papers signed I will order them, hopefully come up with some cash to order a lift from you also
 

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10 has a 3.8. The 3.6 came out in 12. The bigger difference is the auto trans. The ones in 2010 suck without low enough gears.
 

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I run 37s in my '13 JKUR, have 5:13s, and couldn't be happier. At 65 MPH I'm at 2500 RPM, the Jeep will hold speed up moderate inclines, the performance feels slightly better than stock, and fuel economy seems as good as stock if not better.

A fellow Jeeper in my area has a supercharged 3.8 JKU automatic with 4.88s... he wishes he went with 5:13s.

If you travel at higher elevations, you will be much happier with 5:13s

Just my worthless 2cents worth.
 

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I think that's the plan Marcus, I was thinking 5.13's but with so many people saying 4.88 I guess that's gonna be what I do. As soon I get the papers signed I will order them, hopefully come up with some cash to order a lift from you also
I run 37s in my '13 JKUR, have 5:13s, and couldn't be happier. At 65 MPH I'm at 2500 RPM, the Jeep will hold speed up moderate inclines, the performance feels slightly better than stock, and fuel economy seems as good as stock if not better.

A fellow Jeeper in my area has a supercharged 3.8 JKU automatic with 4.88s... he wishes he went with 5:13s.

If you travel at higher elevations, you will be much happier with 5:13s

Just my worthless 2cents worth.
I run 5:13's and could not be happier. I have a Rubicon with a manual transmission. It felt great when I was NA and feels excellent now that I am FI+WMI.

I like the off-road crawl speed and the on road cruising speed. The 5:13's really help pull me out of the hole under hard acceleration as well.
 

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The first couple of responses had me convinced....now not so much :drama:
 

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It really comes down to the ACTUAL driving you do, not wishful.....I'd love to wheel more, just don't have the time. On the beach with it often. But i still love having a Jeep. Im on 37's with 4.56's & auto, driving it 900 miles a week, Phila PA to N.Wildwood NJ, its nearly all flat. Currently getting 18mpg, cruising 65mph at 2200rpm, It has plenty of power to pass. Its a Jeep, I'm not trying to hole shot young bucks at stop lights, so its fine off the line for me, 13mpg city.
 

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Flat highways go 4.88, lots of steep hills on the highway then go 5.13
Agreed with the above statement. I seriously doubt one would be able to tell the difference offroad in 4:1 low range. It really comes down to highway driving and how much it bothers you when the auto is constantly shifting due to lack of power at that RPM. I have 4.88's on 37s but should have went 5.13s.

If one had lots more torque over a broad rpm, i.e. V8 engine, the gearing wouldn't as crucial as with the anemic pentastar.
 

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10a not 2010, it's a 2013 10th anniversary rubicon jku
Ahh. I missed that. So, I will add my 2 cents about 3.6 w 4.88. I have 35's and feel it is spot on for gearing. I just did 3000 mile trip through Colorado and was very happy with the performance. The transmission did not hunt for gears through the passes. I ran about 3000 rpms on the interstate and it was a little over 75 mph. I think 70 is about 2750. I got 16mpg.
I have pulled a 14 foot utility trailer ( 4ft ramp gate) with a mower on the highway and it stays in 5th gear at 60.
I think it would do well with 37's but in a strong head wind or pulling hills I think it would drop a gear. I don't think the new transmission hunts for gears like the old one.
 

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Thought I'd revive an old thread, hope y'all don't mind.
For any of you running 3.6, auto, 37s & 4.88s, do you ever wish you'd have gone with 5.13.
I know this topic has been beaten to death over the years, so apologies in advance. Just wanna make the right choice on Monday when I go in for regear.
 
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