Forum » Tech Forums » Tech Q & A » TJ Gear Change - 3:55 to 4:56

TJ Gear Change - 3:55 to 4:56

  • 18
    Oh Sorry 97 TJ I’m not scared lol, I was just wondering why you're so down on d35's I have had no problem with my diff I also know alot of people that run the d35 with no problems. I’m not afraid to wheel it as I have. I do agree that the d35 and many other vehicle components have been given a bad rap all to do with marketing.

    Since my family has been in the custom rig building for racing and now for the pubilc all of my life, my uncle is the founder and owner of Carl Jantz engineering I think I’m in good hands, if you want serious products for your jeep you can find it here the only thing is you have to know what you want if you can’t find it on his website. They are not afraid to push the envelope and to prove the market is misinforming to make a buck.

    These guys know what they are doing because they do it every day. I also don’t think my family would build something for a family member that is certain to fail little alone customers.

    Any way very happy with my setup as are many others. 
      May 14, 2017 4:58 PM PDT
  • I don't want to scare you, your set up could last you for as long as you own your Jeep, but the D35 axles are widely known as the weakest link. They're not strong enough for 35" tires, especially when a locker is used. Even 33" tires are pushing the upper limits of a D35. I've seen lots of 27 spline D35 shafts with twisted splines or broken from 35" tires and too much throttle. I helped a YJ on 35's with a broken D35 passenger side axle out of the bush 3 summers ago.

    You can get a 30 spline super D35, the axle shafts are the same, larger diameter as the Cryco 8.25 and the D44 but they're still a C clip (like the Cryco 8.25). The entire kit includes shafts, bearings, seals and choice of selectable or auto locker....the spider gears need to come out to accomodate the lager diameter 30 spline shafts. Have a look here

    Driving style is also a factor. If you're not crazy with the gas peddle, you could be OK with 35's on a D35 for a very long time.
    This post was edited by 97TJ at May 13, 2017 9:07 AM PDT
      May 13, 2017 8:28 AM PDT
  • No Rafy you are not missing anything depending on what you used for lockers, you mention selectable lockers, that tells me that you have a stronger center section it also depends on what you used for gears as well but in a nutshell, you have sufficiently made your d35 5 times stronger than Manufactured spec's just by doing what you have mentioned in your post. Your Father and Brother are correct by going to the bigger tire size to take full advantage of your new gear ratio. So, don't worry you are all good 

      May 13, 2017 8:09 AM PDT
  • 18
    [blockquote class='siteforum_icon_quote']97TJ said: Likely just going to stay with 33's but ya never know. If I can find a D44 somewhere at a reasonable price, I might switch.[/blockquote]

    This question may seem stupid. I have been running 35's on my TJ for 3 years now, are you telling me I need to upgrade to a D44? My Father and Brother own a mechanic shop and I went with the 4:56 gears and selectable lockers they installed 35" tires on my Jeep and said that is what I needed to make everything work properly. Now I read what you have done 97 TJ and you’re on 33's am I missing something? 

    This post was edited by Rafy at May 12, 2017 9:29 PM PDT
      May 12, 2017 9:26 PM PDT
  • Likely just going to stay with 33's but ya never know. If I can find a D44 somewhere at a reasonable price, I might switch.
      May 12, 2017 11:01 AM PDT
  • I wish I could be there to help you get it dirty you still running 33's or did you go 35's to match your gears ? This post was edited by Bteck at May 11, 2017 10:21 PM PDT
      May 11, 2017 10:20 PM PDT
  • Finished.... installed a set of 4.56 G2 gears and a Spartan locker in the front with new aluminum diff covers as well as every seal, bearing and front u-joints. Just need to get out and get dirty now!
      May 10, 2017 3:37 PM PDT
  • the first one is always the intimidating I have a very good book if you want to borrow it I would be happy to send it to you and I can be on the phone with you to the most difficult on will be the Dana 30 but with patience and help you can achieve your goal. I almost shit myself when I rebuilt my first diff years ago especially when I took the cover off and seen all the parts in there. Once I got into it and help from my uncle which had been a mechanic for 20 years at the time it turned out to be a very good learning experience the main thing to remember is take your time understand the mechanics of it first. I can send you video as well. another thing is you will read that you will need thousands of dollars worth of tools to do the job right if you have the thousands of dollars worth of tools then it will make the job easy but it can be done without all that. Also just to let you in on a secret buy good quality gear sets like Yukon if you run into trouble or have questions you will get your own personal tech to help you through the prose.  If you buy less you get less.

      October 4, 2016 7:41 PM PDT
  • Thanks Bteck, I'm the first to admit that doing gears by myself is beyond my skill set. Not sure yet how I'm going to get this done. As for the off camber situations, that's why I'm thinking about a LSD for the rear. This way I can disengage the front if needed. It's very rare that I'd find myself in that situation. I suppose I could also use my winch or tow straps to anchor to something as well. Just can't justify the cost for a selectable.

      October 4, 2016 7:11 PM PDT
  • Junkyards you don't need to buy the whole diff you just need the carrier and the shims from both sides so you know what the shim pak measurements are. I f you need help my friend just ask I have done several of these diffs you can make it very difficult or it can be done easy. Just a side note you do understand what these auto lockers can do when driving off-camber right. 

      October 4, 2016 6:20 PM PDT
  • This is not a DD so very little city driving, only to get to and from the trails. I've had other rigs (purchased) with Aussie lockers in the front, never had an issue, they always preformed well on the trail. I know others who have mechanical (lunch box) lockers and all seem to be happy with the performance.

    This time, I'm doing the install so need to educate myself and confirm what pieces I need to make it work. I'll likely go with a Lokka (sold as the Aussie in the US) but can't decide if I want to spend the money on an LSD for the rear. Keeping the cost as low as possible is important, but so is doing this right.

    So, I'm on the hunt for a new D30 carrier, 3.73 and up to get this project started.

      October 4, 2016 4:38 PM PDT
  • Bteck is right I would not go lunchbox in the front well I would not waste my money on any lunchbox no matter how convinced you are about their ability. How much do you want to spend on lockers should be the next question? I would go OX Locker in the front but I’m presuming from what has been posted you drive a lot on the streets? then go with a trutrac for the rear or LSD is fine to. Do your research and make the choices to fit your driving habits and the usual terrain that you wheel if you do a lot of off-camber wheeling then make sure if you are going with an automatic locking locker you don’t go with something that locks as soon as the axle turns. You don’t want lockers operating when you are off camber for sure.

      October 2, 2016 9:40 AM PDT
  • Do not go lunchbox in the front diff you will regret every inch of it on the trail. Myself I would go mechanical front and rear. but if you do a lot of city driving go mechanical front and LDS rear. Another word of advice and I know you probably already have done this is making sure all your ratios will work with the size of tires you are going to run nothing worse than losing a gear selection in your transmission


    Sorry 97TJ I obviously did not read your post well enough



      October 2, 2016 8:27 AM PDT
  • As I stated in my original post, I'm putting a mechanical or "lunch box" in the front so I guess I'll need to find a 3:73 & up carrier.

    Think'n I might add an LSD in the back too since everything will be opened up to do the gears.

      October 1, 2016 6:55 PM PDT
  • First off what kind of locker are you going with if it is a selectable it will replace the carrier if you are going with a lunchbox locker then you will need the 3.73 carrier but yes essentially you will need the 3.73 carrier to go numerically higher. 


    Let us know what you are planning for lockers that will give us more info to give a better answer if that is what you are looking for 97TJ

      October 1, 2016 1:28 PM PDT
  • When I change the gears in my Dana 30/35 from 3:55 to 4:56, I know the front carrier needs to be changed.

    If I put a mechanical locker in the front at the same time, do I still need the carrier or does the locker fit inside the carrier?

    Will the existing 3:55 carrier work with the locker and 4:56 ring & pinion or do I need the carrier for 3:73 and higher?

      October 1, 2016 11:55 AM PDT