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General Forums => The Mess Hall => Topic started by: chrisfranklin on March 31, 2006, 07:00:59 PM
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Lets say you are running a stock Jeep CJ/Wrangler 4 or 6. You've got the D35 axle, which is prone to break, but you want to get a locker.
Here's a Hypothetical situation, one locker, rear, & D35 axle:
When you are off-road and transfer case is engaged, you're going to distribute torque to both the front and rear axles. But, you're climbing and a front wheel leaves the ground, thus causing you to lose the unlocked front end. All of the engine torque is then transferred to the locked rear axle and D35. And depending on other variables (tire size, power, gearing) you may get breakage.
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So, wouldn't it make sense to never run a CJ/Wrangler with a D35 with lockers unless both axles are locked, not just one? Wouldn't this help to insure that the engine torque is always evenly distributed between the front and rear axles off-road, thus reducing opportunities for the D35 to get overloaded (tires size, power, gearing notwithstanding)?
(Or, maybe you could also just do the front, too, and count on weight shift and articulation as enough to keep the rear end planted and torque evenly distributed?)
Nah, nah, nah, grumble, grumble, grumble :lol:
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ARB has the 'Super 35' locker. It takes the 27 spline side gears and upgrades them to 30 splines. Same as a D44. No-one makes stock 30 spline D35 axles, so your only choice are high alloy, chromoly or something. Go easy on the hill climbing and you should be ok.
D35 pinions brake all the time. So do the axles (not the clips, but the axles). If an axle brakes, there's nothing to keep it attached to the housing, and out it comes. If you can keep the axle, and the carrier (or pinion gears) from braking, you've eliminated a few of the D35 quirks.
Start with the rear. Save money and build something. Then sell that D35... You can end up even, or at least not be out that much.
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Not really since the NP/NV231 does not have a central diff so it acts like a spool in the drivetrain This is why you shouldn't run 4wd for very long on dry pavement.
Also, if there was a central differential that wasn't lockable, if you got the front axle in the air all the power would go to the front axle. Power travels to the end with the least resistance.
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Oppp's.....
Did I entirely miss the question?
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Are we talking about the same things here?
I was thinking, in the hypothetical, that if you unweight one wheel on an unlocked front (and no manual hubs), then you lose the axle. So, the entire power of the engine is going to go to the rear wheels, provided they have contact or are locked, right? Which means the D35 gets all the burden as a result.
But, if you were running front and rear lockers (say auto) and a front wheel became unweighted, you'd still have power getting to the ground in the front. Thus the rear wouldn't be takng all of the torque, but would be sharing the load with the front. And, the D35 would be taking less of the load.
So, it makes sense to run front and rear lockers, not just rear, if you are using the D35 rear axle. That way you make sure that the rear end will never be doing the work alone and will thus may face less chance of breakage.
No center diff (i know). And, transfer case is effectively a spool. :? :lol:
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Are we talking about the same things here?
I was thinking, in the hypothetical, that if you unweight one wheel on an unlocked front (and no manual hubs), then you lose the axle. So, the entire power of the engine is going to go to the rear wheels, provided they have contact or are locked, right? Which means the D35 gets all the burden as a result.
Power will still go to that axle and no matter what. Power will be wasted because it will go to the tire that's in the air but power is not redirected to the rear. The rear still has 50% of the power. It does not gain 100% becuase the front axle isn't touching the ground.
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Ok... Front axle, open diff. One tire in the air will lose any traction to the front axle. The power will still be split from the transfer case, but the power going to the front axle will do nothing but head towards the spinning wheel. Least path of resistance.
More power will not be forced to the rear axle. Since the transfer case is splitting the power between front and rear, the rear will not get more of the power.
But, since the rear is doing all the work, whether it's locked or open, it is more likely to break. If it was locked, it could put more strain on it, therefore the strain makes it even more likely to break.
Now locked in the front, the power ratio from the T/C hasn't changed (still 50/50), but the locker eliminates that 'least path of resistance' theory. Traction to at least one tire in the front will assist the vehicle, making it easier to progress up the obstacle. Easier work for the rear axle could help in reducing the chance of breaking.
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Did I get it right this time??
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I believe what you are trying to say is... if you had a locker in the front and rear, then the front 50% would aid in pulling the jeep, whereas with only a rear locker, you'd have to give it more gas to make the rear axle do all of the work to move the jeep since the front axle is rendered useless with one wheel in the air and then no locker. Am i following your train of thought SMC4WD?
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SMC4WD, Wrangler 387, yeah, that's the idea that was coming to me :D. Just, you said it more correctly.
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wow I think I almost learned something there.....hypathecally. are you really trying to justify not swapping axles by adding lockers front and rear. I could be mistaken but isnt the height of the tires averaged into the dana 35 breakage history. I have a 95YJ 2.5 auto 3.73. I just put my TJ flares on and I came across some 30x9.5 BFG ATs that was a deal I could not pass up on tj 5hole rims.I am leaning toward an 8.8(disc)and HP dana30 w/44 ujoints both geared at 4.10 for my next upgade after a trans cooler . I hope this will give me a better base to build upon later(such as lockers and regearing fo possible bigger tires therefor eliminating a fear of breaking dana35 axles
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(tire size, power, gearing)
Did kinda mention the other variables, JackHammer.
But, it would seem that running front/rear lockers could safeguard the D35 a little more, all else being equal. Heck, with front and rear lockers you could probably successfully get away with running an axle "weaker" than the D35 (if there is such a thing :lol: ); this, of course, provided that tire size, power, gearing were within reason.
Would be interesting to see, but wonder how many of those folks who break their D35s were running a locker in the Rear, only. Probably quite a few.
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I see what you are trying to say. Are you planning on stayting on 29"s? The way I feel is I will eventually go bigger then the 30"s I just picked up and I dont want to pay for lockers twice. So I think the axle swap will work for me to start. It is like a triple upgrade. rear disc,added strength, and 4.10 over 3.73. But I will head to your theory when I do lock it up I will lock both at once. probebly detroit rear and selectable front.
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^ i agree with you completely. I have 31" tires on my jeep now (came on there) and when these wear out i'm going to jump up to 33" tires. But definately have no intentions of keeping the D35.
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I guess I see where you're trying to go but I don't think it will work.
There is one thing that will get you into trouble. That's you. A locker will get you deeper into trouble then open diffs. Without any locker, you won't be breaking axle shafts. With a locker, you are more prone. Add larger tires and it's just a waiting game. Now if keep both tires down on the front, having it open won't be a problem. I don't think you'd start picking up the wheels unless you're on a trail that's 3 out of 5. Now with one locker, you will probably end up trying harder then you would with both ends open. This means you'll probably ride the throttle a lot more when stuck. This is when you can really get into trouble. All the hopping and high RPM.
Now if you have two lockers, you can still get into a senario like the one before. Although the front locker might get you a bit further without getting you frustrated. Still when climbing up a tall stairstep or getting one wheel in the air, you don't have that much extra traction from the front. Most of the weight will still be on the rear axle. Power will still be divided 50/50 to each axle but those fromt tires will be spinning and not hooking up.
So what am I saying? If you want more strength, get more strength. Thinking that two locker will save your D35 will give you a false sense of securiety that could leave you high and dry. Or more realistically, cold and wet.
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Would be interesting to see, but wonder how many of those folks who break their D35s were running a locker in the Rear, only.
Yeah, how many of those photos in your D35c FAQ write-up do you think were doing just the forementioned. Not going to put you on spot with your own experiences... :wink: [/quote]
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LOL Someone once said "Lockers get you stuck, a winch gets you un-stuck"
Jeffy's right... Having lockers (fornt and/or rear) only gets you further into the trail, and yes... gives you this fasle sense of security.
But way in the beginning I mentioned that 'Super35' kit. That could give a bit more rear axle strength, and something valuable to sell at a later date.
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Would be interesting to see, but wonder how many of those folks who break their D35s were running a locker in the Rear, only.
Yeah, how many of those photos in your D35c FAQ write-up do you think were doing just the forementioned. Not going to put you on spot with your own experiences...
Didn't hear that answer... That's what I thought. :lol:
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Well if anyone plans to keep the D35c, definately truss it.
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I am probably going to simultaneously install front and rear Aussies on my rig with 29" tires, 4 cyl, and using D35c. Probably never run more than 30-31" tires, so no plans to regear or do some kind of TerraLow either.
I'm probably not going to encounter too much rain, snow, ice in Southern California other than if I go snow-skiing, so the auto lockers don't scare me off too much. Aussies have reviewed well, quiet, strong, warranty regardless of engine, tire-size, etc. Frankly, I am not sure why the US distributor is not pricing them at about $350 per, rather than $230. But, hey, ain't going to gripe.
I may swap D35 shafts to the 30 spline, hell may even do a truss too. Don't have a lot of options here swapping axles, no garage, aftermarket work is expensive here.
But, I am kind of the mind that 2 lockers are the way to go to "keep the 'weight' off the bad knee" that is the D35c. Just have to moderate driver behavior (course with the meager ground clearance afforeded by 29" tires, am only going to go so far anyway :lol:
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If you're sticking with 29's then you aren't really doing anything that will break the D35 unless you plan on jumping it. Those tires are too small to give you adaquate traction for anything more then a 2-2.5 rated Trail.
I've heard of D35's breaking while in 2wd on the street with 31's. As for the D35 article, none of them are on 29's. :lol: :wink:
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Yeah, but, as for the D35 FAQ photos, those guys were all using rear lockers only weren't they? Et Tu, Jeffe with regards to your premier D35 axle break on too large tires? :) :D :lol:
I've heard of D35's breaking while in 2wd on the street with 31's. As for the D35 article, none of them are on 29's.
Yeah, but the guy who broke his D35 with the 31's while in 2wd was running an auto locker in the rear (probably a Detroit) only, rather than an open differential wasn't he? And, was he running a 4 cyl? And, he was probably about 75 years old, right (...more like 23 and driving like he was going to live forever)?
33's and 35's are nice and a little more foot-print, sure, but they are only buying you 2-3 inches of additional ground-clearance over 29s besides just looking cool... They've got guys in India with hangnails longer than 2 inches :lol:
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You get some staun deflators and watch your line on the trail, too, if you are on smaller tires.
Every trail I've done around LA, "Miller Jeep," "Rowher" and the milder "Pilot Rock" was with no lockers and 29s and are a 3-4 on a 5 scale, so I dunno about this 2-2.5 crap. Nahh, I ain't going to drive out and do "the Hammers" once auto-locked front/rear. But, 29s are usable, especially Revos. Does their small size look good? Nah... But, I don't think tires start looking worth a shit on a Jeep until you get to 31s. The 29s work good and my 4 ain't struggling.
With autolockers you can do those same trails going slow uphill and you are never getting out, in advance, to find a line you can handle, unlocked.
Frankly, wouldn't be surprised if, locked front and rear, the Jeep4 and D35 could consistently handle the lower end of the list of some of California's/ Southwest's hardest trails. :P :lol: Rubicon Snubicon
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Yeah, but, as for the D35 FAQ photos, those guys were all using rear lockers only weren't they? Et Tu, Jeffe with regards to your premier D35 axle break on too large tires? :) :D :lol:
You're just beating a dead hrose if you're tring to get people to climb aboard your stage coach.
Yeah, but the guy who broke his D35 with the 31's while in 2wd was running an auto locker in the rear (probably a Detroit) only, rather than an open differential wasn't he? And, was he running a 4 cyl? And, he was probably about 75 years old, right (...more like 23 and driving like he was going to live forever)?
33's and 35's are nice and a little more foot-print, sure, but they are only buying you 2-3 inches of additional ground-clearance over 29s besides just looking cool... They've got guys in India with hangnails longer than 2 inches :lol:
As for 33's and 35's. you're gaining twice the contact patch with a 33 then you would with a 29. That means instead of slipping and sliding you're actually moving. Ground clearance on a deflated 29 vs. a deflated 33 or even a 35 is pretty big.
If you ran a Detroit you wouldn't say that. They are pretty smooth unlike lunchbox lockers like the Auzzie, EZ and Lock-right. You're more likely to break with a Lunchbox then a Detroit.
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As for 33's and 35's. you're gaining twice the contact patch with a 33 then you would with a 29.
A 29" (235/75 15) Bridgestone AT Revo is about 9 inches in width. A 33" Revo (285/75) is 11.5 inches across; a 2.5 inch width difference or about a 25-30% width increase. (C) circumference=Pi x D and C goes up with the 33s too. C on the 33s shows an increase of about 12 inches or about a 15% circumference increase.
The area of the contact patch when going from 29s to 33s Revos shows an increase of about, at most, 40% when math is done; and there is no significant percentage change in the difference when airing out the larger or smaller diamteter tires.
Around a 40% contact patch increase is nothing to sneeze at, for sure. But we're not talking twice the contact patch by any means, unless we're dealing with some kind of too-wide mud tire or something where the tire width doubles when moving from 29-33... :roll: :D
And, for chrissakes you have to add probably 300 pounds or 10% to the weight of your rig to get a 40% contact patch increase due to weight of sturdier wheels/tires/suspension lift & possibly more needed as part of the 33 upgrade. And, you end up with a higher center of gravity, to boot
Frankly, will just air-out, keep weight down, and intake up
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Well, we're talking standard 33's. 12.5" wide. Also keep in mind that when airing down, you do not air down small tires nearly as much as you would with a larger tire. This is because you're giving up ground clearance that you don't have to give up. I wouldn't really air down a tire under 30" lower 15-18 psi. While with larger tires, I've gone down as low as 8-9psi.
Also, that unsprung weight will help when the going gets really rough. The weight will keep the tire in contact with the ground. In this case it's a good thing. CG is also kept pretty low also.
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chrisfranklin
If it interests you; due to my driving style, and intended use of my jeep, my buddy Mike (owner of Twisted Metal) recommended a pair of Lock-Rite's for my D30/D35 setup. I'm sure if you drive like I do (I've been a mechanic in a dealership for years. I don't like to have to fix my own stuff too so I don't miss-use the hardware!), you shouldn't have a lot of problems.
I like my jeep. I don't hurt her unnecessarily. I don't keep the foot in it when traction breaks so I don't break things when I suddenly grab a buried root or rock with a lug and surprise a drive axle. The drive line doesn’t like surprises while it's spinning faster than the jeep is moving for sure! Axles tend to part company if this happens too many times, and that's only one of the many things you can break practicing this ‘technique’.
I guess if you don't drive it like you hate it, your D30/35 will last you longer with proper love and care. But, if you get off on destruction, and exhibit this kind of mechanical mutilation behavior, an axle swap might be a wise choice for you then. You'll probably just break something bigger or more expensive later though... 8)
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Anyone see that detroit 30 spline dana 35 locker that was on ebay for $300? It was slightly used, but hell if i see something like that alittle down the road i might go with a super35 set-up. 30 spline axles are only like 225 i think. I could fab up a bolt on truss pretty easily i think. I've heard the R&P breaking with the super35 set-up, but i've only seen the 4.88s break. If i was planning to stick with the 4.10s, maybe 4.56s... that would help with that issue right? I definately don't beat on my vehicle either as it is a daily.
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Sometimes it is best to not beat a dead horse (as Jeffy put it). Different drivers and different obstacles, different weather conditions and different lines are all taken into consideration. A D35 could last a lifetime for some people. While others can get into their rig, drive into a Quigly Wiggly and BANG! there she goes.
What I use are stats... not written down stats, but people stats... most people I know have broken a D35 with moderate to hard off road use. As well as in the street.
No-one on the site bashes, and I won't do it either. I suggest go with your instincts. Go with what you feel right. It's a Jeep... There are soo many different avenues one can take, and that's one of the biggest selling points on the Jeep.
No where in So. Cal are you? There are a million shops down there. Ya, alot of them are expensive, welcome to SoCal... But Currie, Dynatrac, Tri-county, Alloy USA, and Superior name only a few. 4 Wheel Parts horde that marketplace.
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Hear what you are saying, SMC4WD.
But, just for the information, though, did the guys you know who broke their D35 do it while running front & rear lockers, front-only, rear-only, open front/rear, welded (not going to ask about their tire-size, gearing, engine size/power or other factors that tend to contribute)? :?
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Two of them had factory trac-loks...
One was on a gravel road, that gripped better than he thought, the other was in a parking lot.
I can't speak for the others, but I've been one 3-4 different Jeep/4WD forums...
Also the two were in two at the time...