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I've searched- but I don't understand a gearing question.

George2

NAXJA Forum User
Location
New Hampshire
I've searched, and I guess I STILL don't understand what I really need to buy to make a planned gearchange. Can SOMEBODY please translate to english? Well, maybe simpleton english? Please, no flames- I really have tried to translate 3 days (and nights) of reading from my searches, and I think I'm even more clueless than when I first started!

I have a 1991, with a Dana reverse cut, non-disco 30 in the front, and a Dana 35 in the rear. I am going up in gearing (I ride on 31's, but may one day soon move as far as 33's, and want to be ready). I'm looking at 4.11's, only because I can get matching sets for both ends- but I'd really, REALLY like to go 4.56 NOW, while my finances will allow me to swing the change at once. I'm not too happy that the front D30 has 4.55's available, but I'll take what I can get.

I'm currently 3.55 rear, and 3.54 front, according to the Dana website, and my data tags. (why don't they make matching sets on some sets?) Sorry, that was ANOTHER question, wasn't it? I've always been able to "feel" a difference, even before I stepped up in tire size, but why do they DO that?

4 Wheel Drive is offering a sweet deal on Genuine Gear front and rear sets, and master install kits, so I'm looking HARD, but everyone here swears I need new "spools", so I went searching for THAT subject, and I found "empty" and "loaded" spools available- but I have no idea what I NEED.
Well, I know I need 27 spline, but beyond that, I have no idea if new spider gears are needed, and none of the "search" threads really make the picture clear for me.

Is there ANYONE out there who upgraded, and bought new spools? What (and from whom) did you buy? What in the world did you ask for, because I'm running out of potential "search" words here....

PLEASE, can someone in a similar situation give me an example of what you bought, and how you used it????

This is NOT a "locker" thread, so please don't make the expected offerings there- I can't seem to understand the basics (and I thought I understood as far as 'lockers'), but until I get a hint about what I need for a basic "daily driver" with NO lockers, then I'm afraid you'd be wasting you're time trying to sell me on the locker concept... I just want more beef in towing my popup to Disney for now- and my breathless 4.0 is begging me to hang my head in shame for not understanding.

Please pretend I'm your wide-eyed 5 year old, and your word is gospel...
I'm listening, and hoping you guys can set me straight- so I know what to ask for, when I have to talk to a parts guy, and try and keep him from hosing me for crap I DO NOT need. I'm going to feel like a real unit, when I show up at my new diff/tranny guy with a matching set of 4.56's and install kits, but nothing to PUT THEM INTO. Duh?

Thanks, in advance, for your consideration in responding to what should be a simple question...
 
I'm currently 3.55 rear, and 3.54 front, according to the Dana website, and my data tags. (why don't they make matching sets on some sets?) Sorry, that was ANOTHER question, wasn't it? I've always been able to "feel" a difference, even before I stepped up in tire size, but why do they DO that?
There's almost always a slight ratio difference between front and rear diffs. It's just the way the math works out for a given application, and it's perfectly safe and acceptable.

4 Wheel Drive is offering a sweet deal on Genuine Gear front and rear sets, and master install kits, so I'm looking HARD, but everyone here swears I need new "spools", so I went searching for THAT subject, and I found "empty" and "loaded" spools available- but I have no idea what I NEED.
Well, I know I need 27 spline, but beyond that, I have no idea if new spider gears are needed, and none of the "search" threads really make the picture clear for me.
I'm going to assume you mean carriers. Spools are NOT what you're after. You will need a new carrier for the front differential, but you can re-use the rear. Dana differentials have what's called a "carrier break". Esentially, 2 different sizes to accomodate different ratios. Dana 30's have a carrier break of 3.54 and down/3.73 and up. Dana 35 has a carrier break of 3.23 and down/3.54 and up. Dana 44 has a carrier break of 3.73 and down, 3.92 and up.

Is there ANYONE out there who upgraded, and bought new spools? What (and from whom) did you buy? What in the world did you ask for, because I'm running out of potential "search" words here....
I buy most of my differential parts from Randy's Ring & Pinion. Decent prices, large inventory, great sales person (Jeremy Little, ext. 5533), and I like Yukon Gears and Master Install Kits (they actually have everything you need).

HTH
 
I see that you are trying to make things too coomplicated--
1- The 4.10/4.11, 3.54/3.55 , 4.09/4.11 thing makes no difference It all depends on who did the math that day and how they rounded the numbers off.
2-Spool-Not at all what you want--a solid lock between both axle shafts
3- Carrier- What the ring gear bolts to and where the spider gears or limited slip fit in.Also the "lunch-box lockers"replace these(spider gears) .A carrier change is needed for the D30.This is because of the difference in thickness of the gear sets.I am not sure on the D35 but you may be able to use the same carrier for the 3.55 and 4.10s---some one will correct me for sure.
4- If you order new gear sets get a "Master Install Kit" this will have all seals,shims,ring gear bolts ,bearings and spacers needed to do the job.
5-There are people on this board that sell gears,Rawbrown for one.Randy,s Ring &Pinion treated me well and has a fine rep.
Hope this answers more questions than it creates.
Wayne
 
FWIW most people put a locker or limited slip in since a carrier swap is involved in the front end gear swap, and the labor is already paid for. + paying for an open carrier is silly in my opinion when you can add a measly 200 bucks to the overall cost and end up with a truetrac.
 
I am running 31's as well. I installed 410 gears w/ a 5 speed wish I would of went to 456 just for the same reason to go to 33's.

As for the gear diff. they did it with the intent that the front pulls and the back pushes. It makes for easier steering and when all four are turning.
 
Well if you're on a budget, do you have a junkyard nearby, preferrably one that lets you pull your own parts? If so, go see if they have a 2.5l manual XJ or MJ in the yard that you can grab the axles from since they have 4.10/4.11 gearing and are a straight swap. The yard near me charges $65 for an axle assembly which is way cheaper than trying to regear. I sold the leftover front and rear shafts for $150 on eBay so I actually got paid to do the axle swap.
 
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MJ and XJ front axle assemblies are interchangable....the rear axle assemblies are not....without some fab work anyway. The most likely candidates will be 2.5 or 2.8 with manual trans...at least thats the way it seems in florida...the auto trans units are generally 3.73 down here. But then again the highest natural elevation in florida is like 180 ft...lol.
 
George2 said:
I have a 1991, with a Dana reverse cut, non-disco 30 in the front, and a Dana 35 in the rear. I am going up in gearing (I ride on 31's, but may one day soon move as far as 33's, and want to be ready).

4 Wheel Drive is offering a sweet deal on Genuine Gear front and rear sets.
1-Might want to re-think this before dumping money into a D35
2-Genuine gears SUCK!
 
In my opinion, if you're keeping your axles, go the highest that your front or rear axle will go, then match the ratio in the opposite axle.

Everyone goes up in tire size, it's Jeep nature. ;)

As for gears, I installed Superiors in mine and I like them a lot. No gear howl/whine and nothing abnormal. Just make sure you break in the gears you choose to install.
 
You definatly don't want the Genuine Gears, they are the same as the yukon value Gear sets. Cheap Jap made crap. Definatly go with the Yukon ring and pinion set. They will be much quiter and easier to set up.

The Carrier break in your front just means that all gear ratios below 3.55 have to use one carrier, and all gear ratios 3.73 and up must use another one. From the sound of it, you'll want an open carrier. Dana Spicer makes them and they sell for around $50-$60 each.

Master Install Kits- you will definatly want one of these. Even with expensive tools it is very had to pull bearings off the old carrier without damaging them. a Master install kit will come with ALL the smaller parts that go inside the Differential (pumpkin, chunk, big round thingey in your axle, whatever).

Unless you know you'll be stepping up to 35's just stick with the 4.56's. you're highway MPG will suck with the 31's, but once you move to your 33's you'll be happy. 4.88's are the highest gears made for your D30, but unless you know you're going to step up to 35's, you don't need them. If you're serious about regearing, go to a local 4wd shop and ask questions to one of the salesmen, they'll be more than happy to help you. Typical gear install out the door usually runs between $900-$1100, just depends on the shop.
 
MudDawg said:
MJ and XJ front axle assemblies are interchangable....the rear axle assemblies are not....without some fab work anyway.

Doh! You'd think I would have remembered that since I put XJ axles under my MJ. Aside from being on the wrong side, the spring perches are further apart. Didn't matter to me as I went SOA at the same time.
 
ALL PLAY said:
As for the gear diff. they did it with the intent that the front pulls and the back pushes. It makes for easier steering and when all four are turning.
The slight difference in gear ratios between the different differentials has nothing to do with steering, turning, pushing or pulling. The gear ratio number is based on the ratio of teeth on the ring over teeth on the pinion of a given gear set then rounded to the nearest 100th.
I cant remember the specific ring and pinion numbers for given sets but if you scroll down to the bottom
http://www.ring-pinion.com/content/calculators/RPM.asp,
you can calculate any ratio by inserting the ring gear and pinion gear teeth.
 
Panthers65 said:
Unless you know you'll be stepping up to 35's just stick with the 4.56's. you're highway MPG will suck with the 31's, but once you move to your 33's you'll be happy.
I got better mileage with my 31's than I get with 33's. JIM.
 
Mmmmkay NOW I'm seeing some good advice; stuff that isn't posted in the multitudinious pages of info attached to the gearing stick(ies).

I've heard one opinion about Genuine Gearing sucking... are there any seconds on that vote? Any suggestions for a comparitive-priced alternative? The install alone is going to hone my bank account to a finely-polished "empty" status, but if a different manufacturer selection would help my long-term use, then I'm still listening to ideas, guys. I guess it would eventually be worth the added expense, if I don't have to mess around with this later...

Yes, I'm wholly aware that I'm wasting my coin on building up a 35, but I'm a "fire-trail" rider, not a rocker. After upgrading parts, I'm not really expecting to waste a bunch of axle parts in shallow mud- (here come the flames!) After I get 3 years of "work truck" use, this XJ's going to my daughter- and the extent of it's mods after that will probably be a pink paint job... If I can just have 3 or so years of easy fun with this one, then I've spent my $$$ well, as far as I'm concerned.

What I AM trying to do is get my DD to a point where I can tow my 2200lb pop-up trailer, without lugging down the motor too bad on gentle hills my 4.0 gets winded on WITHOUT the trailer. I'd like to tow from NH to FLA this summer, and really don't want to have to keep answering to the Mrs. about why the jeep keeps downshifting on a 1* grade....

Thanks for all the tips, and suggestions guys!
 
Well..... IMHO, the difference in price between economy and premium gear sets is going to be pretty minimal, compared to the price of the gear change. Personally, I like running Dana gears in Dana axles.
 
bobnoxious said:
31's with what gear ratio? Did you factor in speedo error to your MPG calculation?
I got better mpg's with 31's & 4.56's than I did with 31's & 3.55's. I also got better mpg's with that combo than I am getting now with 4.56's & 33's. I ran the correct speedo gear with each tire/gear change. JIM.
 
ILLXJ said:
I got better mpg's with 31's & 4.56's than I did with 31's & 3.55's. I also got better mpg's with that combo than I am getting now with 4.56's & 33's. I ran the correct speedo gear with each tire/gear change. JIM.

Thanks Jim
 
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