Topic: Axle breakage with 4 bangers - survey

[Crunch]

I know if 'can' happen, but I just wanted to take a quick survey.

Most of the people I know with 33's and 35's on their 4 banger Jeeps have not broken a D30 or D35 axle.  Obviously, the 4 bangers are not capable of generating as much torque as the 6 cylinder motors, and that is likely a major factor.

I'm just curious, who has broken an axle with their 4 banger Jeeps?  Please list the following:
Which axle shaft
Tire Size
Gear's
Was the axle locked, open, have a LSD?
Transfer case (which one, and one setting it was on at the time)
What you were doing at the time (if you were hopping, please include that).

Again, I know it's possible to do, just wondering how many have.

Thanks!

[Jeffy]

Well this will give you a better idea of what actually breaks.

The red Jeep with the guy posing in front of it is a friend.  His Jeep was a 2.5L,  I believe 4.56's although it may of had 4.88's by then.  Stock shafts.

I don't run a D35 anymore.  I got rid of mine before anything happened.

[Crunch]

Thanks Jeffy, the link turned me on to a couple other solutions I didn't know about.  Ultimately, I'm going to replace the D35, no worries.

We're had some club discussions recently about this, but we have only 3 4 banger Jeeps in the club (none of which have broken an axle, all with lockers or LSD, 2 with 33's, 1 with 35's, doing rock crawling).   I figured your forum would be a better place to get some statistics.

[Jeffy]

Thanks Jeffy, the link turned me on to a couple other solutions I didn't know about.  Ultimately, I'm going to replace the D35, no worries.

We're had some club discussions recently about this, but we have only 3 4 banger Jeeps in the club (none of which have broken an axle, all with lockers or LSD, 2 with 33's, 1 with 35's, doing rock crawling).   I figured your forum would be a better place to get some statistics.

One thing you need to take note if is what Year the Jeep is.  If it's 1990 or earlier then it won't have C-clips.

Another things is how much wheeling is done.  Most of the people here are running under 31".  Most of those who run larger then 33's have swapped.  Honestly the D35 is a hit or miss sort of thing.  Some break while others hold up.

Also, take note of what kind of lockers if any.  Lock-rights, EZ's and Auzzies don't enguage as smoothly as a Detroit so that's more of a shock load the axle has to deal with.  The other thing is how heavy the person is on the throttle and if they lift a tire into the air or get it spinning on the ground.  When it hooks iup, the shock will usually break shafts.

I believe most of the spider gear problem stem from the housing bending while offroad.  This is one of the big problems ARB had when developing the locker for the D35.  The flexing would cause the locker to grenade.  They fixed the problem with the newer lockers but a friend of mine went through a few ARB's in his D35 because of it.  Took out his gears too.

As you can see there are many variables.   :nothing:

[jagular7]

I broke a pass. rear axle during a climb. I pushed a little too hard to 'bump' the tire up a little more on the rock face to catch an edge. D35, 4.88, LR in rears, leaning towards driver's side, 4cyl, auto, 2kids and a dog inside.
Now swapped in a 8.8, same gearing, same locker, same everything. Did basically the same thing and climbed it easily.



Oh, btw, high that day was 3 degrees...in the sun maybe 8. The dark color on the rock is from the driver's side tires. Hope this gives you an idea of the climb.

[BlackYJ]

I have seen several guys broke d35 axle shafts.  One was with 33 SSRs, 4.88, and lsd, another was stock gearing and 31s, and another was 35 Crawlers and upgraded D35 shafts.

I run 33 SSRs with 4.10s and an ARB with no problems, and I know a guy on 35s with 4.56 and an ARB with no problems.  The determining factor is the skinny pedal, not always equipment

[chardrc]

ive never gone offroad enough with my jeep to have an opertunity to brake and axle :oops: ..

but we have broken drivers front axels in both my grandpas cj2a and dads cj3a.. with stock axles and lockrightlockers. stock grears.. stock axels

my das had the spliser joint brack cuz had to get on gas when backing over a log adn had the tires turend all the way to the right... but now we got newer stronger axels with ujoints so it shouldnt happen again.. atleast with the stock 4banger in it that started with 60hp and we think is puting out about 90 now..


but that doesnt realy help you

[chrisfranklin]

I maintain my theory that if one runs D30/D35 axles, he would be wise to run lockers in both front and rear, too.  In doing so , he'll generally always have a wheel or two with traction and will have two axles involved in moving the weight of the vehicle at any given time.  This driver will not have to be overly aggressive on the gas to get momentum enough to take him over obstacles, obstacles which would be easily handled, in a slow and methodical fashion, by a front & rear locked vehicle.  

The guys with the jeeps running larger than typical stock tires -- 31s-33s+ --, stock D30/D35 axles and a rear-only locker are the guys probably in most of the broken axle pictures, whether driving 4 or 6 cylinder Jeeps.  Bring on the disagreement  

I run an Aussie in my D30 and open in the D35 -- kind of untradtional to lock the front first, but it has worked well and the weight on climbs shifts to the rear and generally keeps my open D35 working, too.  I do plan to go with a rear Aussie also.  Tire size is realistically limited by the axles, especially D35.  But, like I said, I see reason to believe that using both front and rear lockers, together, will help to  manage the "weak knee" that is the D35 (vs 8.8, D44, D60), provided I stay reasonable and remember tire size, gearing, engine power (swapped), gas pedal usage.

Some of you guys might be going, "front and rear lockers...that's going to cost a fortune..."  Well, I wouldn't call it a fortune because I had an Aussie auto-locker bought, shipped and installed for $400 total -- $800 if front and rear installed; DIY front and rear would be $500.  The Aussies are warrantied for use with any tire size, are quiet and very well reviewed by users, strength-wise.  Sure, your old carriers are still going to be in place, as are your stock axles and axle tubes.  But, the synergy caused by running two lockers will likely remove stress from those aforementioned stock parts in many hard off-road situations.

[chardrc]

hmm interesting conscept and it makes sence also

[Erik]

non c clip stock axles in my jeep.  geared 4.88.   39.5" boggers.  3 years ive broken 1 shaft, and 1 set of spider gears.  i don't wheel often and both breakages have occured on the street while doing stupid stuff driving like an idiot.

[Jeffy]

hmm interesting conscept and it makes sence also

It's been hashed out here to some extent.

Like I've probably mentioned a few times before one of the main causes for breaks is shock load.  Get a tire in the air with open diffs and you're stick since all the power goes to the one wheel.  (You're stuck, nothing broke.)  Add a locker into the situation and both tires will turn.  The tire with traction will still try to dig in.  When it does, it will bring the high side back down and grab.  If you're not crawling slow (mostly the case when you're not geared low enough to idle up...) the tire will have some speed and if it hooks up hard, the shock load will snap the axle shaft.

The rear axle takes most of the load.  That's why they are always larger then the front.   Having a locker in the front helps take some of the work load off the rear but will not fix the problem.  Like I mentioned in my first post axle shafts aren't the only problem.  Broken spider gears are common also.  This means they are still using an open differential and are not locked.  This about as common as broken shafts.

Oh and BTW: rear lunchbox lockers seem to wear faster then the front.  Many of guy's I know who run Truckhaven, and Johnson Valley, used to see a lot of them beat up.  Since the front sees less action, they live longer.  (Most run Detroits or ARB in the rear.)

If anything lockers break stuff because they make you try harder.

 

[chardrc]

ya and you can get that shock on your axles when you are going throw sand adn they gain and lose traction..

[Jeffy]

ya and you can get that shock on your axles when you are going throw sand adn they gain and lose traction..

Sand is actually pretty forgiving.  Wheel hop is caused by inproper air pressure, I think.

[chrisfranklin]

Frankly, I'd like to believe that with two lunchboxed (and were talking Construction Worker "lunchbox," not Sailor Moon "lunchbox" for the Aussies   )  your worst case scenario is having two axles with one wheel unweighted on each and the other two spinning on dusty rocks looking for traction.  Basically, this means you'd have two wheels spinning in the dust -- say front/left and rear/right or vice versa. I still say that your wheel spin, even like this, is going to be greatly moderated by the fact that you have two tires (say, front/left and rear/right) huntring for traction, not one.  

The 4 Banger, powerhouse that it is,  (maybe even the "HO 6," too) is just not likely going to have the juice to break something in the aforementioned situation when the unweighted wheels land. Furthermore, with the two said wheels in the dust, your traction "area" is still doubled (and put a different way, your powerful 4's stock 150 or so lb/ft of torque -- multiplied by your respective drive-train -- is working at spinning two wheels instead of one).   When your Jeep's unweighted wheels land, front and rear, they are also not likely to be spinning at the same speed as would a rear wheel on a Jeep with an autolocker on the rear-axle only -- The 4's torque doesn't turn in to that of a supercharged Chevy V8 when it has autolockers front and rear (wish it did, though :)   )

I think dual lunch box lockers, say Aussies, basically work like "Risk Management" -- sh$ts going to happen, you just want to take steps to minimize the chance.  Can you still break an axle with dual lunchies, say a D35?  Sure.  Are the chances of this reduced, provided all else on your Jeep stays equal ("all else" being tire size, gas pedal usage, gearing, engine size, Driver "Gusto," trail difficulty).  I'd say "Yes."

(Only downside with dual lunch is ice/snow/rain traction at higher speed in 4WD High.  I'm in the Sun Belt, so I don't see much of the slick weather unless I actively hunt around for it by heading to the mountains -- and there I'd probably just stay 2WD unless I got stuck with my set-up.  If you are in the Pacific Northwest, Colorado, New England, Canada you probably don't want to mess with an autolocker in your front end -- get a True Trac or an ARB/OX.  And, personally, I would, admittedly, rather have ARBS/OX/Detroits (not the EZs) -- frankly, with the right axles, etc. these do an even better job of "Risk Management."  But, I live in a mostly dry area, don't have a ton of disposable income, and I speculate that the strength of the Aussies, their bang-for-the-buck, and their anti-axle-breakage potential when running them front and rear, D30/D35C, are all High -- so, that's what I am sticking with.  

[SMC4WD]

The 4 Banger, powerhouse that it is, (maybe even the "HO 6," too) is just not likely going to have the juice to break something in the aforementioned situation when the unweighted wheels land.

Are you under estimating the motor, or over estimating the axle.  

Chris, I gotta tell ya, I love your writings...  Your explanations are very in depth and thorough...  But I still think you overestimate the strength of a 'smaller' Dana axle (30/35).  Shock load is pretty intense.  And it entirely rests on 'driver instincts'.  Your scenario is accurate, but the moment the momentum stops, the axles (could) give.  

I do not know the technical terminology here, so work with me on this one...  

Rockwell scale -
The Rockwell scale characterizes the indentation hardness of materials through the depth of penetration of an indenter, loaded on a material sample and compared to the penetration in some reference material. It is one of several definitions of hardness in materials science. It involves the application of a minor load followed by a major load, and then noting the hardness value directly from a dial. Its chief advantage is its ability to display hardness values directly, thus obviating tedious calculations involved in other hardness measurement techniques. Also, the relatively simple and inexpensive setup enables its installation in college laboratories.

It is typically used in engineering and metallurgy and is most common in the USA. Its commercial popularity arises from its speed, reliability, robustness, resolution and small area of indentation.
From Wikipedia, the free encyclopedia

http://www.gordonengland.co.uk/hardness/rockwell.htm - Rockwell Hardness Test

Too much scientific reading for me...  The jist of it is, the axles need to twist a teeny bit, or break a lot.  It's a fine line between the two.   Stock axles are not as strong as custom axles.  Chromoly, 4140 steel, whatever the grade axle, they're stronger than stock.  Housings bend too.