The Very 1st Jeep JK Wrangler
4.88 & 5.13 Gear Installation & Test

One of the things that makes the all new 2007 Jeep JK Wrangler so cool is that unlike any other Jeep Wrangler before it, this thing can be made to clear 35″ tires or more with little more than a moderate 3″-4″ short arm suspension lift and without any problems.  Well, almost without any problems anyway.  Of course, with bigger tires comes the need to regear your axles to a ratio designed to accomodate them and while the new Jeep JK Wrangler still uses a Dana 30 (or Dana 44 up front for the Rubicon Models) and a Dana 44 in the rear, it turns out that the ring and pinion used is not the same design as previous years and so nothing had been available to those in need of regearing.  I say “had” because with the expert help of Off Road Evolution, Superior Axle & Gear has just become the very first aftermarket manufacturer to produce, install and test a prototype 4.88 and 5.13 ring and pinion for the Dana 44 rear axle.  And, I’m happy to say that they will be installing and testing a front set today.

Unfortunately, I wasn’t able to cover the installation and testing of the 4.88 gears that went into Kevin McNulty’s 4Wheel Drive & Sport Utility Rescue Green Jeep JK Rubicon Unlimited that’s sitting on top of 35″ tires, but I was fortunate enough to cover the 5.13’s that went into Mel Wade’s Off Road Evolution Silver JK Sahara Unlimited that’s sitting on 37″ tires.  And, after going for a test drive before and after the installation, I can tell you that the results are outstanding!

Now, I should note that when I went out for the first test drive, I was actually pleasantly surprised at how well the Off Road Evolution JK ran on 37’s even with stock 4.10 gears.  Granted, it was nothing to write home about but it was certainly more tollerable than I was expecting.  However, once the new Superior 5.13 gears were installed, I’ll tell you, Mel’s JK bit in right off the line, moved like it had purpose and pushed those 37’s like they weren’t even there and with ample power to spare.  As far as real performance numbers go, according to the Lorance GPS unit that Mel has in his JK, he was now able to do 75 MPH at 2500 RPM in 4th gear whereas he couldn’t even do 75 MPH in 4th before the regear.  Need I say more.

To see photos of the prototype Superior 5.13 ring and pinion, comparison shots of it next to the factory 4.10’s and installation photos, click on the link below:

Superior Axle & Gear Jeep JK Wrangler 5.13 Ring & Pinion Installation

Eddie

Special Thanks:  I would like to thank Superior Axle & Gear and for giving me the inside scoop on this much desired new Jeep JK Wrangler product and Off Road Evolution for allowing me to observe the installation of these new gears and to test them out.

29 Comments so far

  1. Max February 8th, 2007 11:36 pm

    Sounds great. How do the larger tires and regear effect the electrics (ABS,ESP,traction control)? What did they do to correct it?

  2. Thedon February 9th, 2007 7:02 pm

    Did you have to change the case to run the 5.13 gears?

  3. wayoflife February 9th, 2007 7:37 pm

    Hi Max,
    So far, we have not experienced any ill effects on the ABS/ESP from the larger tires and regear. After installing a lift, you just need to make sure that your steering wheel is centered and you should be good to go.

    Hi Thedon,
    No, the 5.13’s bolted right up to the factory Dana 44 carrier.

    Eddie

  4. Mike R February 10th, 2007 3:54 am

    I can’t help but notice that both are non Rubicon models. Will they fit the new locker carrier in the Rubicon?

  5. wayoflife February 10th, 2007 11:11 am

    Not true. The 4.88’s were installed into a Rubicon Unlimited and the 5.13’s into a Sahara Unlimited. Need I say, yes, they will fit the new Dana 44 locker carrier for the Rubicon. :)

    Eddie

  6. Nick February 15th, 2007 12:07 pm

    Are they available yet for the Rubicon Unlimited or are these just beta types?

  7. wayoflife February 15th, 2007 12:09 pm

    Hi Nick, from what I am told, they should be shipping to dealers in about a week.

    Eddie

  8. Brian Dunning February 16th, 2007 6:29 pm

    Anyone making 4.56 gears for the Rubi? That’s closer to correct, according to the chart at http://www.superioraxle.com/htmlfolder/gearcalculator.html

  9. wayoflife February 16th, 2007 9:13 pm

    To the best of my knowledge, no. Most manufacturers are only focusing new gears that will work with bigger tires.

  10. jay01th February 19th, 2007 1:03 am

    Hi, well, I plan to get some 34 inch tires on my Rubi, What do you think I will expect to pay (that is if I need 4.88’s)? Thanks Jay

  11. mar February 23rd, 2007 8:10 pm

    will these gears work in the 3.21 gear ratio axles.

  12. Aaron August 27th, 2007 10:53 am

    If your JK has the factory 3.21 ratio, the 4.88 will require the replacement of the carrier. If your non-rubi has a tow package, it has a dana 44 rear with 4.10, and will NOT need a carrier change. You can call your Jeep dealership with the VIN and they will provide all the necessary information.

  13. Travis September 3rd, 2007 5:04 pm

    I’ve installed a BDS 4.5″, and 4.88 superior gears. About 65% of the time I get ABS, and ESP lights, along with that, I don’t get cruise control when these lights are illuminated. What might be causing this?

  14. wayoflife September 4th, 2007 3:18 pm

    Hi Travis, do you have a 2-door? Also, have you made sure your steering wheel is centered? If it’s even a little bit off, you will have ESP/BAS issues.

    Eddie

  15. Travis September 9th, 2007 12:53 pm

    I have the 4-door. I did not do the install, although I have reason to believe that the steering wheel was not perfectly centered (besides the lights I’m getting). The shop that did the work is about 3 hours from me, and I would like to explore more convenient options for correcting this (vice 6 hours of driving). Any ideas?? Thanks for the info so far,

    Travis

    p.s. Will the superior shafts (front) allow me to lock up the front (with 35×14.50×16’s) and not have to constantly worry about snapping them? …when they are available…

  16. wayoflife September 10th, 2007 2:21 am

    Hey Travis, click on this link and scroll down to step #89 to see how to recenter your steering wheel:

    http://project-jk.com/jeep-jk-write-ups/full-traction-suspension-jeep-jk-wrangler-3-ultimate-lift-installation-write-up

    As far as your question about Superior shafts go, when they become available, they will give you piece of mind to run 35’s.

    Eddie

  17. Bill September 28th, 2007 10:29 pm

    I have a JK 2 door which I installed a Rusty’s off road 3 1/4 inch lift and am running Mickey thompson baja 35×12.50×17’s I do not have a clue as to what gears I should be running. What would you recommend? I have been told leave them at 4.10 go to 4.56 4.88 and 5.13 I just don’t know what to do. This is my daily driver so I need to be able to move. Please any help would be great it is all just to confusing for me.

  18. Bill September 28th, 2007 10:34 pm

    PS what gears should i run in the front and which ones in the rear? My JK is the X model so i have the dana 30 in the front and the 44 in the rear thanks again

  19. wayoflife September 30th, 2007 1:24 am

    Hi Bill, you need to run the same gear ratio front and rear and for 35″ tires, I would recommend no less than 4.88’s. That’ll bring you back to stock performance. If you wish to get a little more out of your Jeep, go with 5.13’s as they will give you a lot more pep (that’s what I’m running now). The downside to them is they will burn more gas.

    Eddie

  20. AJ July 2nd, 2008 2:52 am

    I raised my wifes 4 door JK and put 32″ tires on it with 15″ Mickey Thompson wheels. I only have a 3″ lift on it and want to put a set of 35″ tires on it. Do I really have to regear it?
    I lifted my H2 and have a set of 38″ Mickey T’s on 20’s and regeared it, but if I go from 32’s on her jeep to 35’s is it necessary. If so, what ratio should I go with. 4.88’s or 5.13’s or nothing at all.
    Thanks.
    signed,
    still confused even after lifting my H2

  21. Dominic January 20th, 2009 4:25 pm

    sorry im a lil scared for regearing my plan was the mopar lift with 37inch tires on my 4dr rubi but when it came to regearing i read on so many forum have problems with their elockers after regearing. yet no answer on why and no straight answer on fixing it. do you guys have any ideas before i go with my plans cause im willing to wait want to do it right the first time..

  22. Eli March 11th, 2009 12:36 am

    I have a wrangler X and I’m running 35’s but planning to change them to 37’s. Therefore, I’m planning to regear and I went to a store to ask about some gears and they said that I will have to buy lockers as well to fill up some space made by the new and bigger gears. Is that true? Thanks!!

  23. stan April 28th, 2012 8:26 pm

    plz help ! i have 07 jk x model 6sp with 34’s =315/70R 17’s goodyear and 4.88 gear and having a noise from the rear diffrential ! would it be better going to 5.13 on manual trans. or re use 4.88 … ive runned 4.88 for 4 years now is it time tp replace or renew or what?

  24. wayoflife April 29th, 2012 11:49 pm

    5.13’s is a really high ratio for just 35’s and a manual and you will be running your RPM’s really high at highway speeds. also, on a dana 30, your pinion will be really really small and will be a potential breaking point. i would stick with 4.88’s. don’t know what kind of noise you have so i can’t help you there.

  25. stan May 1st, 2012 7:27 pm

    thank you for replying but ihave dana 44 and the noise mixed like loud humming feels grinding and when i opened the rear diff lug i found little tiny or lets say if you run a magnet thru the sand and it picks iron so any how i flushed it and reoiled it but still! do you think my barring are wearing outs? its been 4 years.

  26. stan May 1st, 2012 7:34 pm

    or do i need diffrent drive shaft ? or maybe tilting the rear diff … i heard tons of stories and solutions and dont know what to do?

  27. wayoflife May 2nd, 2012 12:51 pm

    based on the kind of sound you are describing, if yo’re still running a factory shaft, it could be that the bearing in your cv joint are going bad.

  28. Alex January 10th, 2013 7:48 pm

    Dear Sirs,
    I have JK 3,8L mod 08′ Automatic gear, kindly i could like to inform me i’m planing to change to 37” instead of 33′ and of course i need pinion to install ok i know, also i have 3” lift and i plus 1,5” more it is the max lift to work and drive good
    I have front 30 dana and rear 44 dana with no lockers.

    Do i have any others problems in the axles may damage any others parts? need to change something else?

  29. victor reed April 3rd, 2014 8:41 am

    I have a 09 Sahara 4in lift running 35s. Put 4:88 in and still have a hard time staying in overdrive. Should I go with 5:13s.

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