Jeep Wrangler Forum - Reply to Topic
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > JK Jeep Wrangler Forum > JK General Discussion Forum > Proper gearing for 2012 auto to run 35's

Join Wrangler Forum Today


Thread: Proper gearing for 2012 auto to run 35's Reply to Thread
Title:
  
Message:
Post Icons
You may choose an icon for your message from the following list:
 

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Additional Options
Miscellaneous Options

Topic Review (Newest First)
05-31-2012 01:13 AM
Braveheart12JK
Quote:
Originally Posted by Mortalis5509

I'm pretty sure Jeep doesn't make there own gears but buys them from someone. Any gear company that makes decent stuff and someone who knows what they are doing will have a great outcome.
Half true here. Lol. They are factory gears, however a gear company def makes them for Jeep and just brands them as jeep parts, however I'm not sure how u find out or who knows. On the other hand, the second part is not as accurate. I've had many gear set changes before, and the shop that does my gears is well known on this forum, and is highly recommended in this area and they will def tell u that some gear manufacturers, although their gears are strong, are prone to noisiness, no matter how well they are set up. No one wants a noisy whiny gear set. Lol. To each their own though. Lol
05-30-2012 11:08 PM
Mortalis5509
Quote:
Originally Posted by Braveheart12JK View Post
I have a 2012 JK auto. I had 3.21's factory. I got a 2.5" lift and 33" Duratracs. My acceleration wasn't bad after, but it was noticeably worse passing or uphill. I talked to an excellent 4x4 shop in my area that had done my lift and tires, and we decided 4.10's with a LSD was the way to go given that I don't wheel it regularly and I still do a fair amount of hwy driving weekly. We went with an Auburn HP LSD and Jeep 4.10 gears. Paid a bit extra for Jeep ring and pinions, but they are known to be quieter than most aftermarket at that ratio. I like the power I got back and they're nice and quiet. I can cruise at 75 at 2850 RPM's as well
I'm pretty sure Jeep doesn't make there own gears but buys them from someone. Any gear company that makes decent stuff and someone who knows what they are doing will have a great outcome.
05-30-2012 08:28 PM
en480c4 I just drove 1,100 miles in my 6 speed 2012 JKU with an AEV 3.5 SC and 35" KM2's the weekend after the install. My trip took me from Southern Maine to Gettysburg, PA, which had me going through rolling hills in CT, NY & PA. I'm still running the stock 3.21 gears, which meant I was running around 2,200 - 2,300 rpm in 5th at my cruising speed of 72-73. I only used 6th on some big downhills over 75 mph.

I give all this background because I can confidently say that after this trip I went from on the fence between regearing to 4.11 and 4.56 to knowing for sure that 4.56 is the right choice for me. I was hitting about the same rpms in 5th at the same speeds as I would be in 6th with the 4.11 gears. With the added rolling resistance of the 35s and added wind resistance, I had to downshift to maintain speed on any significant hill on the highway. Once I shifted down to 4th and was up in the 2,500 rpm range, the Jeep could keep going. It also did better in 5th when I stayed above 76 or so, where my rpms stayed in that 2,500 range. But it definitely struggled to find sufficient hp at those lower rpms.

As a more minor note, my calculated mileage seemed to be a little higer when I kept the rpms up a bit on the highway. I was just over 17 mpg on the tanks where I kept it running a little higher, where it dropped just below 17 mpg on the tank where I didnt downshift as much and tried to power through some of those hills. Hardly scientific, as it's a small sample size. But it aligns with what others have said.

So there you have it... My reasoning and experience that has led me to choose 4.56 gears for my '12 6 speed. I should be right around 2,550 at 70 with my KM2s which measure 33.5". Now I just need to start squirreling away the money!

Edit: I know mine is a 6 speed, but the gearing is similar, and the plus with the manual is you can control what gear you're in, which lets you simulate other gearing. So I figured I'd share.
05-30-2012 04:38 PM
InvertChaos
Quote:
Originally Posted by flyracin17

Hey guys, thanks for all the info. This chart is BA! Definately going with 4.10s from what I've gathered. Wanna keep hearing opinions though. Anyone have any price ranges on what a set of rings, pinions, and carriers is gonna run me installed? How much could I save doing it myself? I'm not against it.
I think the price average is between $1200-1800 out the door for a ring and pinion change depending on labor charge. If you want a locker or anything else installed at the same time you can add that to the total. My master install kits for my D30 and D44 plus a new rear carrier was ~$600 with the labor being $250/axle plus $100 worth of shop supplies and fluid. There are very few people that would take this on themselves as the gears have to be set up perfectly to last and it involves some very expensive tools and a lot of precision.
05-30-2012 04:31 PM
flyracin17
Quote:
Originally Posted by XJ Knight View Post


Go to 4x4 shop.. Tell them what gearing you want. Talk to them about where they can get the gearing from. there are a few different manufactures out there. Pick company you want you gears from. wait for them to say come and get your jeep. pay them (1200 +/- 300). drive off with a smile
Hey guys, thanks for all the info. This chart is BA! Definately going with 4.10s from what I've gathered. Wanna keep hearing opinions though. Anyone have any price ranges on what a set of rings, pinions, and carriers is gonna run me installed? How much could I save doing it myself? I'm not against it.
05-30-2012 03:48 PM
clvnmcd
Quote:
Originally Posted by MTH View Post
I've never driven a 3.6, but I don't think this is right.

4.10s will no doubt work great with 35s on a 3.6. But with a manual trans that only gets you to less than 2200 RPMs at 70 mph in 6th gear. Compare that to a dyno showing the power curve of the 3.6 and you'll see you're leaving quite a bit of power on the table and the engine has a long way to go while still being comfortable.

So while I've heard of course that the 3.6 with 4.10s does great with 35s, I think that's more a testament to the power of the engine rather than proper gearing. Toss some 4.56s or 4.88s in there and you'd be spinning in the 2500 to 2600 RPM range at 70 mph--still well within the engine's comfort zone--and you'd really feel it pull.
I haven't driven the 2012 regeared to a 4.56 or 4.88, but by seat of the pants feel with the 4.10's I would say you are right on the money. There is adequate power, but I certainly think there would be room for improvement with a little gearing help. I usually won't drop into 6th gear until at least 65 and that's when just cruising.
05-30-2012 03:04 PM
MTH
Quote:
Originally Posted by smess View Post
that is for a 2007-2010

4.10 at the most for the 2012 with 35's
I've never driven a 3.6, but I don't think this is right.

4.10s will no doubt work great with 35s on a 3.6. But with a manual trans that only gets you to less than 2200 RPMs at 70 mph in 6th gear. Compare that to a dyno showing the power curve of the 3.6 and you'll see you're leaving quite a bit of power on the table and the engine has a long way to go while still being comfortable.

So while I've heard of course that the 3.6 with 4.10s does great with 35s, I think that's more a testament to the power of the engine rather than proper gearing. Toss some 4.56s or 4.88s in there and you'd be spinning in the 2500 to 2600 RPM range at 70 mph--still well within the engine's comfort zone--and you'd really feel it pull.
05-30-2012 02:55 PM
clvnmcd I'm running 35's in a manual JKUR with 4.10 gearing and it works fine.
05-30-2012 02:50 PM
smess
Quote:
Originally Posted by Wharfrat View Post
I would go for 4.56 or 4.88 myself. IMHO you can never be geared too deeply (within reason of course).

that is for a 2007-2010

4.10 at the most for the 2012 with 35's
05-30-2012 10:13 AM
InvertChaos Isn't the new carrier only like $40?
05-30-2012 10:11 AM
Johnny6 I'm running about 2200 RPM w/33" tires and stock 3.21s at 75 MPH. I was pleasantly surprised there wasn't much difference.........just a slight power loss and 1 MPG. I do plan to go to 35" tires and it looks like 4:10 is the suggestion that shows up the most for the 2012.
05-30-2012 09:26 AM
dwindeck
Quote:
Originally Posted by Braveheart12JK View Post
I have a 2012 JK auto. I had 3.21's factory. I got a 2.5" lift and 33" Duratracs. My acceleration wasn't bad after, but it was noticeably worse passing or uphill. I talked to an excellent 4x4 shop in my area that had done my lift and tires, and we decided 4.10's with a LSD was the way to go given that I don't wheel it regularly and I still do a fair amount of hwy driving weekly. We went with an Auburn HP LSD and Jeep 4.10 gears. Paid a bit extra for Jeep ring and pinions, but they are known to be quieter than most aftermarket at that ratio. I like the power I got back and they're nice and quiet. I can cruise at 75 at 2850 RPM's as well
Something doesn't compute there. Your RPM's are 200+/- higher then they should be. Did you have the PCM reflashed for your new gears?
05-30-2012 06:50 AM
XJ Knight

Go to 4x4 shop.. Tell them what gearing you want. Talk to them about where they can get the gearing from. there are a few different manufactures out there. Pick company you want you gears from. wait for them to say come and get your jeep. pay them (1200 +/- 300). drive off with a smile
05-30-2012 06:42 AM
Wharfrat I would go for 4.56 or 4.88 myself. IMHO you can never be geared too deeply (within reason of course).
05-30-2012 03:00 AM
LorraineKerri You wouldn't need a new housing
05-30-2012 02:10 AM
Braveheart12JK I have a 2012 JK auto. I had 3.21's factory. I got a 2.5" lift and 33" Duratracs. My acceleration wasn't bad after, but it was noticeably worse passing or uphill. I talked to an excellent 4x4 shop in my area that had done my lift and tires, and we decided 4.10's with a LSD was the way to go given that I don't wheel it regularly and I still do a fair amount of hwy driving weekly. We went with an Auburn HP LSD and Jeep 4.10 gears. Paid a bit extra for Jeep ring and pinions, but they are known to be quieter than most aftermarket at that ratio. I like the power I got back and they're nice and quiet. I can cruise at 75 at 2850 RPM's as well
05-30-2012 12:57 AM
JeepHerz You can also get 4.56 gears now.There is a 2012 gear chart around here somewhere that's really helpful. It shows rpms at 70 mph for each gear ratio/tire diameter. I've been quoted $900-$1400 for either 4.56 or 4.10s.
05-29-2012 10:57 PM
Mig888 I have 3.73 with 35s and I think it is a good fit for the 35s
05-29-2012 10:56 PM
Dylanjwhall I'd go with 4.10s It's a good mid point an incase for some reason you go bigger it'll still work out
05-29-2012 10:52 PM
flyracin17 I currently have 3.21s, so what are suggestions for purchasing? Who's a good dealer and are the gears model of jeep specific or just d30/d44 specific?
05-29-2012 07:41 PM
dwindeck You wouldn't need a new housing, just the carrier. and I wouldn't go lower then 4.10, and if you have 3.73 your good.
05-29-2012 05:58 PM
MTH What gears do you have now? 3.21s?
05-29-2012 05:35 PM
pluke the 2 we are running 37s and our 2012 with stock 410s and there isnt any issues or a need to gear lower.
.02 save your money.
05-29-2012 05:28 PM
flyracin17
Proper gearing for 2012 auto to run 35's

Ok guys. So I need to know the best place to get gears for my D30 in front and D44 in rear. I also need opinions for gear size. I want 4.10 gears but read you need to replace the housing if you go bigger than 3.73. I'd be ok with 3.73 but am having problems finding them and most websites make it seem like they are model specific. I thought the only thing that mattered for fitting was if its a D30 or D44, etc. Appreciate any help out there.

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -5. The time now is 10:04 AM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC