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Unread 08-20-2013, 05:33 PM   #1
dserbin
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2012 JK sport 3.21-35"

Hey, so ive been reading around about the 3.21 with 35" tires which is what i have. with a 4"lift. And so far everyone has been saying it's not so good for off roading.. well, its my first jeep and tbh i wont be doing anything crazy right off the start. Would this set up be ok for on road applications as a DD. I live in Canada so we get some nasty *** winters up here, will that have any effect on it as well? And one more thing, What should i go with if i do decide to re-gear? Is there anything else i would have to add to it also?

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Unread 08-20-2013, 06:14 PM   #2
SoK66
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Even with the Pentastar 3.6L that's a really unfortunate gear ratio. Some reporta that the Rubis are OK with 4.10s & 35s, but I'd be looking at 4.56s - 4.88s. I have the earlier 3.8L and originally ran 4.88s. It was fine until the long mountain grades, then it was a frickin' screaming stone. I switched them out to 5.38s last Fall. Better in all respects. It still screams on grades but can actually accelerate and highway mileage actually improved.
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Unread 08-20-2013, 06:28 PM   #3
rha600
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I am very happy with my 4.10s here in Florida. Up north in some hills I'd want more, but I can't even begin to imagine what it must be like with 3.21s
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Unread 08-20-2013, 10:21 PM   #4
Lammy
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I'm curious about how daily driving a 2012+ 6speed (or auto I guess) is with 3.21 gears and 35" tires. I'm planning on doing it, I just want to know what to expect.
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Unread 08-20-2013, 10:56 PM   #5
dserbin
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haha, i wouldnt know. i pick it up on sunday i think. thanks for the replies guys. so a 4.56s would be good eh? would i have to replace anything else? i read somewhere on here that somebody had to replace their frontarms of some sort, i dont quite remember what they where though. Also, would driving this got the tile being have any negative effect on anything?
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Unread 08-21-2013, 04:52 AM   #6
tankinyj
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Its not that bad for 3.21s with the 6 speed and 35s on the 3.6 Its doggy, but just subtract one gear from normal. I revved around 2k cruising with shift points up around 3-3.5k. 5th gear was highway only. I got my 4.56s and I love them
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Unread 08-21-2013, 06:11 AM   #7
Butterjeep
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I run 33's with 3.73's and I would say I am borderline so yeah, you would need a regear for sure I would say. Spinning too tall of a gear can fry your clutch or torque converter so I'd say regear.
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Unread 08-21-2013, 07:41 AM   #8
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i have a pentastar w/auto trans and 3.73 with 35s. Its not TOO bad once you get used to it. I will eventually be upgrading to 4.88s to allow it to cruise better and not be searching for the right gear going up steep hills and gain some better mpg.

i couldn't imagine 3.21s w/35s though.
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Unread 08-21-2013, 04:55 PM   #9
dserbin
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whats this pentastar i keep hearing about? is it an engine?
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Unread 08-21-2013, 05:05 PM   #10
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Quote:
Originally Posted by dserbin
whats this pentastar i keep hearing about? is it an engine?
Yes. Also known as the Penta-Jesus and Penta-Ticker.
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Unread 08-21-2013, 05:24 PM   #11
awinski
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Quote:
Originally Posted by dserbin View Post
haha, i wouldnt know. i pick it up on sunday i think. thanks for the replies guys. so a 4.56s would be good eh? would i have to replace anything else? i read somewhere on here that somebody had to replace their frontarms of some sort, i dont quite remember what they where though. Also, would driving this got the tile being have any negative effect on anything?
To answer somr of your questions. First of all for regear id go 4.10-4.88 what you choose will be fine all depending on preference. The 3.6l penastar loves to spin so dont fear the 4.88s. But it does not need them imo.
For me. I run 4.10 with 37s. Im perfectly content for the moment, rwgear is last of my worries. Especially since im seeing 19mpg hwy and 16 city. Better than I did stock with the 32s!!!
There are two guys in our club that run 3.21s here in pa with 35s. They run blue, black, and red trails with minor issues. Do they lug, yes, but its still doable. Regear when you have the money.
For lift. Research my friend, and for a damn long time! Youll find what you need. Id say leveling kit - 2.5" lift if you dont plan to offroad much.
And penastar is the 2012+ engine.. for now
Anything else?
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Unread 08-28-2013, 11:32 AM   #12
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I run 33's with 3.21 on 2013 jku. No issues. I definitely wouldn't go bigger without regearing though!
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Unread 08-28-2013, 12:43 PM   #13
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3.21's have no business in a Jeep. 3.21's and 35's is just a bad combination plain and simple. Unfortunately many people put up with poor gearing by convincing themselves that "it's not that bad".

When I was running 3.73's and 33's, I wanted 4.10 gears.

I'm now running 35's and 4.88's. They are perfect for me. If I where to see more highway speeds (70mph+), 4.56's would be a better choice.

I can see a flatlander getting by with and being comfortable with 4.10's and 35's.


If you had 3.73's, I could see putting up with the lack of gears for a little while. Since you have 3.21's, do yourself a favor and regear. It will be money well spent and you will not regret it.

Here is a great deal on quality gears.
http://www.4ws.com/jeep-wrangler-jk-...ront-rear.html
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Unread 08-28-2013, 12:48 PM   #14
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Quote:
Originally Posted by Lammy View Post
I'm curious about how daily driving a 2012+ 6speed (or auto I guess) is with 3.21 gears and 35" tires. I'm planning on doing it, I just want to know what to expect.


Poor fuel economy, the complete loss of 6th and sometimes 5th gear, high RPMs, and sluggish performance that will take most of the enjoyment out of driving a Jeep.
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Unread 08-28-2013, 01:47 PM   #15
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Who makes those 4WS gears?
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