Calling all regeared '12 JKs!! Need help please!
JK Jedi
Joined: Nov 2010
Posts: 4,406
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From: Gray, GA
Thread Starter
JK Enthusiast
Joined: May 2012
Posts: 134
Likes: 0
From: Laguna Niguel, CA
Thanks for weighing in on this one, guys. For those who said I shouldn't bother regearing, I probably should have given you an idea of what I'm expericing since the lift... 6th gear is almost useless with any kind of uphill grade or headwind. With the stock 32s and the 4.10s, I was having a hard time holding speed up hills on the highway. It has since gotten worse with the 37s, or course. I can barely hold my uphill speed in 5th now. I want to get into something that I can use without having to hunt for gears when on the road without pulling anything, but I wouldn't mind having to downshift while tugging a trailer behind me. The mixed things you all have just said is pretty much the same thing that I have been hearing from others too. I wish I knew someone who had a '12 on 37s with 5.13s and a 6 speed so I could just find out for myself before I dropped the cash! Haha.. What a pain.
JK Enthusiast
Joined: Jul 2011
Posts: 237
Likes: 0
From: San Antonio, TX
Thanks for weighing in on this one, guys. For those who said I shouldn't bother regearing, I probably should have given you an idea of what I'm expericing since the lift... 6th gear is almost useless with any kind of uphill grade or headwind. With the stock 32s and the 4.10s, I was having a hard time holding speed up hills on the highway. It has since gotten worse with the 37s, or course. I can barely hold my uphill speed in 5th now. I want to get into something that I can use without having to hunt for gears when on the road without pulling anything, but I wouldn't mind having to downshift while tugging a trailer behind me. The mixed things you all have just said is pretty much the same thing that I have been hearing from others too. I wish I knew someone who had a '12 on 37s with 5.13s and a 6 speed so I could just find out for myself before I dropped the cash! Haha.. What a pain.
I'm running 37" tires and 4.56 gears with no issues, but I have a 2012 JKU Rubicon auto with a 3.5" lift. Even when I had my 35" tires and 4.10 gears, I never had a problem going up a hill. If I had a stick instead of an auto, I'd change out my 4.56 gears and run 4.88 gearing because the stick has a taller overdrive for the 6th gear than the overdrive that is in the 5 speed auto.
Edit: It just occurred to me, do you know what version head is installed on the driver's side of your engine? The AA version and some AB versions have been having problems? I had my driver's side head replaced with an AC version. Some people are reporting loss of power that was restored after the dealer inspected their JK's heads and found a bad one that needed to get replaced. Lack of power might be your main issue, not the lift. If you need a head replacement, you could get back lost power and maybe better mpg after the dealer replaces it.
Last edited by bo9roadking; May 1, 2013 at 05:01 PM.
Thread Starter
JK Enthusiast
Joined: May 2012
Posts: 134
Likes: 0
From: Laguna Niguel, CA
Since day one of owning it, it's struggled at maintaining uphill speed in 6th on long uphill grades on the highway. I can gain speed uphill in 5th, but 6th is too tall and I can't keep my uphill momentum. Does that make more sense? Once I lifted it, naturally it got worse. I would like to get my gearing just a hair lower than it was when it was stock so I don't have to fight hills in 6th, can get more use out of 4-hi, and be able to tow a trailer without strain.
JK Enthusiast
Joined: Sep 2010
Posts: 324
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From: Tulsa, OK
Since day one of owning it, it's struggled at maintaining uphill speed in 6th on long uphill grades on the highway. I can gain speed uphill in 5th, but 6th is too tall and I can't keep my uphill momentum. Does that make more sense? Once I lifted it, naturally it got worse. I would like to get my gearing just a hair lower than it was when it was stock so I don't have to fight hills in 6th, can get more use out of 4-hi, and be able to tow a trailer without strain.
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