Howdy,
I'm sure this has been answered 1,000+ times but I can find a definitive answer. I have a 2011 Wrangler Unlimited with the 3.8L engine with an automatic transmission. I'm running a 35" tire and a 2.5" lift. What kind of gearing should I upgrade to? I've seen charts that say 4.56 is the best for everyday use and some that say as much as 5.13. We want to get into more trail riding but nothing extreme and from where we live it would be a lot of highway driving to get anywhere to go offroading. I'm looking for decent performance on the trails without it screaming going down the highway at 70 mph. After I figure out which gearing to get; is there a good website to order everything I need? I don't want to get to the shop and find out I need $400 of other stuff to go with the gearing.
Also, I'd like to have lockers installed at some point and I'm thinking that it would be a good idea to have it done at the same time as the gearing. What are some decent lockers? I know ARB's are good but at $1,000 each they may be a little out of my price range.
4.56 would be good for your situation. If you have the money to do the gearing and lockers at the same time i'd recommend it just to save shop time. Another thing to look into now that your going to be locking with 35's is upgraded axle shafts. There are a ton of different style lockers out there, ARB is a good brand, i personally wasnt a huge fan of using it on my front locker, I went with an Aussie up front and its amazing, performs flawlessly on road and works great off road without having to worry about switching on and off. similar to the aussie/spartan/lock right style is the Detroit which ive used in the rear and loved. I currently have an Eaton E locker in the rear and I live it so far.
I've been leaning towards the 4.88 gears but I'm afraid it's going to be running at a high RPM at highway speeds. Anyone use 4.88s or higher with the unlimited 3.8L automatic?
Thanks for the feedback guys. It sounds like the 4.88s are the way to go with my setup. Just need to decide on lockers now. Are the automatic lockers reliable? No issues with them?
I recommend a Tru-Trac for the front and rear differentials. These traction devises are very smooth and reliable. They provide traction to the tire that is getting the traction which is what you need on the trail. The Tru-trac units are great for on and off road use. They have no clutches or clips to wear out are break like a factory Trac-Lok has.
They not require in special additives or posi lube, just gear quality gl5 or better
petroleum gear oil. They are a lot less expensive than air lockers or e-lockers. The time to install them is at the same time as the gear install. I would recommend the
G/2 4.88 ring and pinion kits and master bearing install kits and the Tru-Tracs. Also
it would be a good idea to put in new Dana Spicer front inner axle seals at the same time. I recommend 4wheelparts, they have good prices and gear savy technicians to
do the differential work.
I prefer selectable lockers. ON when you NEED them. OFF when you do not want them.
Course I also like a clutch. Auto lockers might be a better choice if you prefer an auto tranny.
And cost wise.... doing gearing and lockers should save some money.
Which automatic came in the 2011?
And go here.
You need to decide on the ratio which works for you.
Anyone who says "you need".... has no idea what "you need".
Plug in the data to the GrimReaperCalculator... or any similar calculator. Read the rpm/speed data.... take a drive... try whatever gear gives you that rpm/speed and decide if that sound/power works for you. Often if you are dropping to a lower ratio, dropping a gear with your current ratio will give a similar rpm.
There's a couple of links at the top of the page to give you the basics on gearing and also the basics on the pros and cons of all the locker options (hopefully without trying to push any one choice over another).
I've been laid up sick for a while so I didn't chime in on this thread but if you have any specific questions I can help you with, let me know and I'll try to help.
Thanks for transmission info, that helped a lot. Judging from the calculator 4.88s or 5.13s would work out really well for me. I'll probably go the 5.13 route to future proof a little bit. We may want to tow something small or go to a 37" tire. Great info on lockers too. Is there a brand that you prefer over the others?
Thanks for transmission info, that helped a lot. Judging from the calculator 4.88s or 5.13s would work out really well for me. I'll probably go the 5.13 route to future proof a little bit. We may want to tow something small or go to a 37" tire. Great info on lockers too. Is there a brand that you prefer over the others?
I think you have the D30 in the front. I would go with 4.88's. The pinion on a D30 5.13 is really small. I would be afraid of breaking it with 35's and wouldn't want to do any offroading with a stock D30 with 5.13's and 37's. If you are sticking with the D30, I would recommend 4.88's, sleeve and gusset, 35's, and a selectable locker or open for the front. Depending on difficulty of trails, a good LSD in the rear like the Tru-Trac will get you through the light stuff, but I prefer a selectable like an ARB, E-Locker, etc. Definitely on when you want it, and definitely off when you don't.
I have only done the Eaton E-Locker and Auburn Gear ECTED.
The Eaton unit has been perfect for me. Open when I need it and locked at the flip of a switch. I have them front and rear in my truck. The JK has one in the front.
I put an ECTED in the rear of my JK. I love the limited slip. It's really good all around for better traction and fantastic street manners. It doesn't quite lock 100% so I sometimes have a little wheel slip in the rear but I still have little trouble getting over most obstacles. At least no trouble related to the locker. I'm a little under-geared for rock crawling so I can't quite get low and slow enough yet but that's a different issue.
I don't have any experience with ARB lockers. Though I rarely, if ever, hear of anyone having a problem with one that's installed properly.
I hear good things about OX lockers too.
I don't have any experience with automatic lockers or aftermarket limited slips. So I can't really offer any advice on those.
Thanks for the input. After I "decided" on the 5.13s I was reading some reviews about them and seen a few people that had issues with them being chewed up or broken. 4.88s may be the better option for reasons you mentioned. I do already have the sleeves and gussets sitting in my garage waiting to be installed. I'm just going to have them, gears, and lockers done all at once so it will save some labor costs.
Derf: I was looking at the Eaton's so you just helped narrow down my choice quite a bit.
KYLiberty: I just noticed in your signature that you have a 2011, running 35" tires, and have 5.13 gearing but recommended the 4.88 gears. Do you have issues with your setup? Just wondering.
I have a Rubicon with a sleeved and gusseted D44 in the front that is getting RCV's, new ball joints, and a truss installed currently. It has bigger, stronger ring and pinion gears. If I wasn't planning on going to 37's soon, I probably would have gone with 4.88's just because of the little bit of 70 mph interstate driving I do and being a little stronger.
My rear diff is also a D44 like yours, but is 32 spline instead of 30, which is a little stronger and has Ten Factory axle shafts and a truss being installed currently.
I was of the opinion these were the correct gearing charts:
(Courtesy of tnjeep forum)
I'm turning just over 2500 at 70MPH with my 5.38s and they seriously add oomph to take offs.
Yes, I am planning on going to 37s once these 35s are dead, but I would never advocate for lower than a 5.13 in the OPs situation. I think they would be seriously disappointed in anything less while running 35s.
EDIT:
2011 JKUR 3.8L Auto, 35x12.50R17 Cooper STT, 5.38 gears
Grimscale, I agree that 5.13's would give the OP better performance and that combined with wanting to go to 37's is why I'm running 5.13's. However, I have a Rubicon like you do. For the OP with a D30 and wanting to do some offroading, personally I would give up the performance for a little more strength. Just my opinion. Of course, if money is no object for the OP, I would recommend a front axle swap to something stronger and 5.13's or 5.38's with 37's, and an upgrade to 35 spline axle shafts in back or an axle swap for it too. Not my checkbook though.
Look around forum for sale pages for lockers before you give up on ARB and buy something else. I paid $500 for my RD36 and $450 for my RD114 with a broken $80 part.
having a differential on the street, and a spool on demand, is really awesome.
With 35s, 4.10s and the 4speed auto...
70mph is 1910rpm in OD, 4th and 2750rpm in DIRECT, 3rd.
4.88 70mph is 2200rpm, 3rd is 3200rpm.
5.13 70mph is 2380rpm, 3rd is 3450rpm.
After reading the OPs use...
"We want to get into more trail riding but nothing extreme and from where we live it would be a lot of highway driving to get anywhere to go offroading. I'm looking for decent performance on the trails without it screaming going down the highway at 70 mph."
I'd keep the 4.10. I'd rather have the ability to drop rpms on the long easy straights. And if i drop a gear at 70mph it puts me right in the sweet spot of 2700rpm for power. The challenge with the 42RLE is the 0.69OD Ratio. Keeping the rear end tall enough for 3rd gear... without hitting 4000rpm at 75mph.
Howdy, I'm sure this has been answered 1,000+ times but I can find a definitive answer. I have a 2011 Wrangler Unlimited with the 3.8L engine with an automatic transmission. I'm running a 35" tire and a 2.5" lift. What kind of gearing should I upgrade to? I've seen charts that say 4.56 is the best for everyday use and some that say as much as 5.13. We want to get into more trail riding but nothing extreme and from where we live it would be a lot of highway driving to get anywhere to go offroading. I'm looking for decent performance on the trails without it screaming going down the highway at 70 mph. After I figure out which gearing to get; is there a good website to order everything I need? I don't want to get to the shop and find out I need $400 of other stuff to go with the gearing. Also, I'd like to have lockers installed at some point and I'm thinking that it would be a good idea to have it done at the same time as the gearing. What are some decent lockers? I know ARB's are good but at $1,000 each they may be a little out of my price range.
I had a Trans Am in the '70s. I regeared from 2.73 to 4.10. Tires were about 26"? The difference WAS amazing..... So was my fuel mileage and the noise... not to mention shortening the life of my 455 by 40%.
Kicked ass off the stop lights and at the Christmas Tree. SUCKED everywhere else.
[I]"from where we live it would be a lot of highway driving to get anywhere to go offroading. I'm looking for decent performance on the trails without it screaming going down the highway at 70 mph"[/I]
This says to me 5.13 is not your best choice.
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