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Regear or 4:1 low range

3K views 15 replies 11 participants last post by  Happy Joe 
#1 ·
I have 33's and 3.07's. I want to replace the rear axle eventually so I dont wanna re-gear it. would a 4:1 tera low be worth the money? Would it break my d35? I take it easy when I'm in the rocks but it doesnt crawl slow enough.
 
#2 ·
well lemme give you an example....
i have a very well built dana 30. about all you can get for one is on mine.
never broke anything, until i installed the 4.3 atlas, then every wheeling trip i bust a front u joint! the extra torque from teh lower geared atlas was too much for a stock size joint.
now i have 30 spline chromo's instead of 27 spline, and super joints for u joints. so hopefully i wont be busting everything everytime out!
IMO, you would be risking more damage/breakage if you put the 4:1 gears in the 231 without building the axles.
if it were me, i would get the new axle in there, regear them both, then build the front 30 if you keep it. that way, you will be ready for lower t/case gearing when the time comes.
i wouldnt have thaught it would be so bad in low range right now, hell scott was wheeling on 42's with 4.10 gears, never had a problem off road....
martin
 
#3 · (Edited)
I would replace the axles before going with the 4:1 case gears. The 4:1 will make it work better in low range (with a chance of increased breakage) but will do nothing for street performance.
I have 4:1 gears (with 4.56 in the diffs). and can break axles/ujoints by goosing the gas pedal if I use boggers on high traction surfaces. I have gotten by through a combination of; D44 rear, careful driving and relatively low traction tires (12.50 x 35 MTs). When I get the chance and feel motivated I will change the front to a D44 (with a D44 rear to match the track width), however, even that may be marginal for tires bigger than 35s.

I would look for a set of 4 cyl YJ axles (or Cherokee axles, these will take more work to make them fit) with 4:10 gears (verify gears before getting), they should be cheap/free, and will work with careful driving on 33s. (Note; they did offer a "metric ton" heavy duty option in Jeep pickups and Cherokees, which had a rear D44 but these are kinda hard to find). Then save up (and hunt) for rear 8.8 and front D44 axles (you might be able to get the rear 8.8 cheap/free but the front D44 will probably be spendy and harder to find. You had better figure on re-gearing both axles during the upgrade.

Enjoy!
 
#9 ·
do a 8.8 rear since they come from the factory with 4.10 and they are stronger then the 44 in everyway...and then do a HP 30 cherokee front axle straight bolt in and build them two for a while unless you can find a front 44 for cheap....trust me i would know and i have the same set up and love it...especially with the aussie in the front and the e-locker coming for the rear....also there is no point in throwing a tera 4:1 reduction since its what 1,000$ for that you can get the rock-trac from the rubicon that has a 4:1 in it or save up for an ATLAS and then be done for good.
 
#12 ·
X2... I just got done with this very swap last weekend. 8.8 in the rear with 4.10s and HP 30 out of an XJ in the front. I too was running 33s with 3.07 gears and it was pretty well gutless. I'm really happy with the 4.10s... The RPMs on the highway will take some getting used to but believe it or not I think my gas mileage has actually improved. I'll find out for sure today when I fill up the tank. But to echo everybody else, I wouldn't modify the Xfer case yet... More expensive, more likely to break stuff etc.. I haven't had a chance for a shakedown run with my new gears yet, we still have snow on the ground but soon.:2thumbsup:
 
#10 ·
Let's look at this as two different problems. First, the 3.07's simply will not perform well on road at highway speeds in front of 33" tires. That being said, something in the order (minimum) of 3.73's will put your engine back in the meat of the power band helping both power and economy. It will also help lower your crawl ratio. Once the axles are geared properly, you can address the crawl ratio. If this is a play rig, your axle gearing can cover this by choosing better crawling gears at the expense of highway driving. If it is a DD or sees highway driving, then you will need to address your crawl ratio as a separate problem. The atlas or Tera low are both ways to help using the t case. Another is a swap to a trans with a "granny" low such as the T18 or one of the SM (GM) offerings. the Novak website is a good place to start for info on these swaps.
 
#11 · (Edited)
It is likely though that you can get a complete set of used 4.10 axles from a 4 cylinder cheaper than you can re-gear one end (even if you do the work yourself). You will have to put the word out and shop arround to get the best deal.

In my experience 4.27 gears are a near perfect match to 33 inch tires but you couldn't not get reverse cut D30 gears for this ratio the last time I looked. One step either way from 4.27 give you a choice between 4.11/4.10 and 4.56 ratios. In all cases re-gearing an axle is expensive if you have it done by a competent axle man (people inexperienced in this work will often blow the install, which will leave you on the trail broke (both pocketbook and vehicle).

If you can locate a 4.10 8.8 for the rear (it ought to be cheap) then you could go with a (cheap) D30, 4 cyl 4.10 front until you can afford a matching track width d44 front and 4.10 gears. Note you will, likely, need to cut the suspension mounts off of the 8.8 and weld on a set of spring perches.

It should be noted, though, that for normal medium to hard trails the 4.10 D30 front will probably be strong enough to last with the 33 in tires (depending on your driving style).

Enjoy!
 
#14 ·
The teralow kit is more expensive then just getting a regear. You'd be better off to do a 8.8 or 44 axle swap and regear while in the process. The 4:1 kit will put more torque to the axle but it's not a matter of "if" it's a matter of "when" it will break. Don't sink any money into the d35. Like others have mentioned get an 8.8 rear that already has 4.10 gears and the LSD. Then regear the front to match.
 
#15 ·
As it useally goes... I am in the unpopular zone again.

I disagree!:eek:
MY 4 to 1 is THE BEST mod on my Jeep:thumbsup:
I love it.
It does suck in the snow as the 4 to 1 slows me waaay down and it is hard to get the speed to bash. But snow bashing is now done in 4hi instead, no big deal.

I did my tera low INSTEAD of doing a gear job. The difference in price between a tera low and a 2 axle gear job is huge. The on street manners were not altered in the process either. That is a good thing in my eyes as going from 3.07 to say 4.10 gears will have a negitive effect on street gas mileage, and at $3.50 a gallon, this HAS TO BE CONCSDERED.

The tera low only is noticed when in 4lo, the rest of the time it is completely insivisable.

What the 4 to 1 did on a rocky trail was amazing. I can now climb some things I could not before. Slowing the rig down in the rocks is so important and helps to keep from slashing around and breaking things I don't want to break.

All that said:
I do not have a stock drivetrain!
The 4 to 1 would absolutly trash a stock drivetrain, so beware.
It produces 50% more torque from the trans case back, and will just tear the stock driveshaft and axles(D30,35) up.
Tera low has a big disclaimer on the 4 to 1 about this.
 
#16 ·
For crawling they are great (I always do deep snow in 4 hi for wheel speed) (try the slick rock in Moab I guarantee grins);
...if (big if, as noted above) the axles are strong enough to support the increased low range torque (a D35 rear with 33s and 4:1 would be looking for problems, IMO, many see problems with 33s with stock 'case gearing) It would better to go with 4.10s and an 8.8 than expect the D35 to last.

For big tires with improper gearing street performance needs to be corrected first to maintain mileage, IMO. Although, an automatic with small gears and 33s, might be acceptable to some. The mileage would depend a lot on the ratio of highway to city traffic; somewhat lower than stock axle gearing tending to give slightly better city (stop and go) mileage, and slightly (33s are more than slightly) higher axle gearing/tire size tending to give a little better highway mileage. The manufactures spend a lot of time trying to get the best compromise so I typically recommend re-gearing to maintain the vehicle rpm when going to larger tires (though a slight performance/mileage hit is usually felt as the larger rubber takes more energy to start rolling and maintain speed).

Enjoy!
 
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