Calgary Jeep Association
4x4 Related Groups => Tech Talk => Topic started by: FirstTimer on March 21, 2011, 04:52:51 PM
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I was hoping I could get some insight into whether or not it would be less expensive to track down a set of axles with the appropriate gearing to run 33inch tires then it would be to re-gear the current DANA 35 and DANA 30 I have in my 02 Jeep TJ Sport 4.0L? Additionally, what would my options be for a swap that was basically bolt in, if in fact I did find a set of axles that were geared right?
Currently, I have sourced out a couple of options.
1. Swapping out my axles for a members axles who is running 4.10 gearing on his dana 35 and 30 as he is upgrading to ford 8inch axles.
2. 98 zj dana 35 and 30 3.55 gearing with coils and disc brakes front and back (will this even fit?)
3. your suggestions.
Keep in mind this is my DD driver and I am not an Uber wheeler, this summer will be my first summer wheeling. So I intend to be light on the gas and will be running less aggressive MT tires.
THANKS!!!!
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Swapping the TJ axles with 4:10s is going to be the easiest. The rear ZJ axle will not be a direct bolt it for the TJ. I assume you have 3.07 gears now?
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3.07 is indeed what I have!
How much power will I lose if I go to a 4.10 ratio, as I've heard 3.56 is best?
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Someone correct me if I'm wrong, but I believe (with a higher gearing) you will be getting more power transferred to the wheels at a loss of some top speed.
Swapping in larger tires will then balance this somewhat. One tire revolution = you move one circumference of distance, so with a larger tire, you go further. Higher top speed at a loss of torque. Also larger tires = heavier, so a little more of your engine's power goes to rotating them, and less power makes it to the road.
Also (you didn't mention this, so just in case), your speedometer will be out if you don't replace the speedometer gear (http://www.stu-offroad.com/engine/speedo/speed1.htm) in your transfer case.
(Check that for your year, I know the 2003s and higher could have some ECU parameter adjusted by the dealership to fix the speedometer)
There are some good charts out there to match up which speedometer gear you need for your tire size, and your gearing:
http://www.raingler.com/tech/speedoChart.asp (http://www.raingler.com/tech/speedoChart.asp)
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You always gear lower, numerically higher, to compensate for larger diameter tires.
If you swapped in axles with4.10's it wouldn't be bad at all on the road with 33" tires. You would be slightly more fuel effecient as your highway revs will be lower than factory. I currently run 3.73 and its ok but i hope to re gear soon
overall your ideal ratio depends what transmission you have
5 spd -you would re-gear to 4.56 for 33" tires, if your not wheelin it alot maybe even 4.10 would be ideal
Auto- 4.10 is ideal
If your running 33" tires your best bet is to get rid of your d35 and find something stronger, by stronger I also mean signifigantly more expensive. Again if you drive it on the road more and wheel it lightly, just sticking with d35 would be ok, certainly not ideal. D35's fail on a regular basis. If it stays just on the road go with 4.10 d30/d35 combo
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You always gear lower, numerically higher, to compensate for larger diameter tires.
Errr, good point Jrama.
I should rephrase:
Someone correct me if I'm wrong, but I believe (with a higher gearing) you will be getting more power transferred to the wheels at a loss of some top speed.
to:
Someone correct me if I'm wrong, but I believe (with a higher gear ratio) you will be getting more power transferred to the wheels at a loss of some top speed.
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rubicons came with 4.10's and 31's as a TJ. With a 5 speed tranny, that was good. With Auto it was not good enough.
If Auto, you need higher ratio number, with manual tranny, slightly less.
35's and Auto are dialed in with 5.13.
37's and manual are dialed in with 5.13.
4.88 is the lowest NUMBER i would go if i was running 33 or 35.
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Oh, i would not buy axles that were 30/35 combo for any reason. You would be better building your own 30/35 with gears and stronger axle shafts.
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+1 for not throwing money at a D35 rear axle. It severely limits your other choices, like how big of a tire you can go, whether or not to install a locker in the diff, and how much trail abuse it can take before breaking.
If you want I may soon be selling a Chrysler 8.25" rear axle from an XJ with 3.55 gearing.
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4.10's were great with my SIX speed and 32's. 4.10's are just okay with my SIX speed and 35's....but I'd be happier with 4.88's or 5.13's.
Don't bother spending money on a half-arsed solution. If you're going to spend money, spend money on what you really want...not on something that's kinda sorta maybe what you want. If you want 33's and don't have a fancy-dancy 4:1 transfer case, shorter gears are better :)
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rubicons came with 4.10's and 31's as a TJ. With a 5 speed tranny, that was good. With Auto it was not good enough.
If Auto, you need higher ratio number, with manual tranny, slightly less.
35's and Auto are dialed in with 5.13.
37's and manual are dialed in with 5.13.
4.88 is the lowest NUMBER i would go if i was running 33 or 35.
Interesting, I was thinking of going to the popularly suggested 4.56 ratio for my 33" tires which will be replaced by 35" in due time. Either way this little calculator helps you work things out. As for my numbers with the auto trans, those were the popular opinions I came across browsing through JF. I think i may reconsider and go to 4.88
http://www.manoian.net/jeep/gear_ratio_calculator.html
Trans=Nv3550
4.88 and 33" tires places 110 kph at near to 2700 rpm
4.56 and 33" tires places 110kph at near 2500 rpm
4.10 and 33" tires places 110kph at 2200 rpm
3.73 and 33" tires puts you near 2000 rpm
I wasn't really too intent on regearing till I drove a jeep with 4.88 gears on 35's and realized how terrible my jeep was in comparison.
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To clarify a few of my jeep specs, it is a five speed manual, 4.0 L 6cylinder with the np 231 t-case.
The axle option I would consider buying from one of the members although it is a 30 35 combo, it is much less then regearing my current 30 35 combo, leaving me money to maybe truss the axles or turn the 35 into a super 35...any thoughts? additionally to be honest I am looking for the simplest solution as I don't want to pay someone out the butt to fab in some crazy strong axle combo that I wont truly need...for now...
are there any dana 44 options that will bolt right in?
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i hear ya.
i drove mine with 4.10's and 37's and swore it was ok. But as soon as i went 5.13, i realized how not ok 4.10's were. lol.
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35's and Auto are dialed in with 5.13.
This is what I had on my 2003 Rubicon and it was a PERFECT combination. About 2,500 RPM at 110k which put it in the perfect range to make power.
It also gave me the BEST gas mileage ever in that Jeep, better than stock, better than 4.10's with 33"s and better than 4,10's with 35"s.
Vince
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How cheap are the axles, what sort of shape are they in and do you plan on ever going bigger than 33" tire, do you want to keep the stock ABS?
There's nothing wrong with going to a rear d35 if staying 33" and under, lots of bolt on upgrades to make it comparable to a D44 without the hassle of getting new mounts put on and you can build it in stages to offset the cost. Now if the axle is in poor shape and needs a rebuild anyway you may be better off finding a TJ D44 rear and having it regeared. I don't think the standard TJ D44 came with 4.10s from the factory(correct me if I'm wrong), except the Rubicon which is big bucks and hard to find used.
Anything NOT out of a TJ will require a fair bit of fabbing to fit(including a ZJ axle).
4.10s is good with 33s if doing lots of street driving, 4.56s with 33s are better offroad but run a higher RPM on the highway and can hurt fuel economy.
If you think you might go bigger than 33" then bite the bullet now and spend some coin on a HD rear end.
Also consider that the brakes on a D30/D35 combo are marginal at best with 33" tires.
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call stan at northridge; you can order up a brand new rear 44 with gears, lockers etc for 2500. bolt in. any kind of axle swap you consider, if you can't weld and do the work yourself, is going to be very costly. any axle will cost $$$$ to swap in.......
if you could find TJ axles with 4.10s that'd be an option too i guess........ but the condition of said axles may be questionable, and if you are going through all that trouble, it would be a wise idea to have them rebuilt.... and if you are just going to pay someone to install them, might as well just regar yours.......
or,keep your stock axles and regear them. be prepared to drop about 800 - 1000 on gears, plus another 1000 - 1500 on install... a 'super 35' kit will run you an additional 1500 or so, if you go with an ARB air locker.
axles are a great upgrade, but by far the most expensive. long story short............ break out the wallet... its gonna cost you; there are no 'cheap' options with axles.
take a look at these.... go big or go home ;)
http://www.northridge4x4.ca/proddetail.php?prod=PKG-DANA44-REAR&cat=38
http://www.northridge4x4.ca/proddetail.php?prod=PKG-DANA44-FRONT&cat=38
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can hurt fuel economy.
What the hell is fuel economy? Haven't seen that unicorn since I sold my CRX (and then proceeded to buy 3 Jeeps).
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There is some great information regarding gearing here:
http://www.naxja.org/forum/showpost.php?p=377955&postcount=1
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Haha! Tell me about it! I just bought 5.9 ZJ. 13mpg and requires premium to boot.
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but it will go like a raped ape(man)!!
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For a stick I agree with the above link. However after owning a few offroad autos and sticks and converting a rig from auto to stick and another from stick to auto I can say with all confidence that an auto can get away with less gearing than a stick. Why? Because the torque converter in an auto acts like a torque multiplier and takes up the slack. The ONLY time in an auto that you will see a difference is in a downhill descent, the auto will almost freewheel while a stick will out brake it EVERY time.
My dad's XJ has 33s and 4.10s with an auto and works VERY well on street and trail. Also it feels better than my 5psd XJ did with 4.10s and 31s except for downhill. Best part is that I got those diffs for $300 for the pair from a 4cyl XJ and spent $200 on a used lockright for it. So for $500 bucks we got a set of bolt it diffs with a locker and 4.10s. Its been pushing 33" Bias Ply Truxus for 3 years now. He carries the shafts from his old axles, just in case but has never needed them. Hard to beat that price and he is never going over 33s so no worries there.
You really need to be honest with yourself about how far you want to go with this hobby and how much you want to spend, in the short and long term. Don't forget that you could always re-sell those 4.10 diffs down the road if you change plans. Nothing wrong with growing and changing things as your rig evolves even if it does cost a bit more money.
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going with 33" tires, 4.10 is OK. no 5th gear on the highway unless going down the cochrane hill.
buying and swapping axles would be my choice of the two options. this will leave you with your old axle shafts (front and rear) to carry around when you wheel.... rear shafts being more important.
this combo will allow you lots of time to see if you like wheeling enough to start saving for a better axle combination... which is more than just axles. shafts and lockers and gearing then comes drive shafts and slip yoke etc.... you never know where you will finish off.
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... you never know where you will finish off.
...do we ever finish off? If there's a light at the end of this tunnel I haven't seen it (maybe I'm just going deeper into the tunnel :P)
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There's nothing wrong with going to a rear d35 if staying 33" and under, lots of bolt on upgrades to make it comparable to a D44 without the hassle of getting new mounts put on and you can build it in stages to offset the cost. Now if the axle is in poor shape and needs a rebuild anyway you may be better off finding a TJ D44 rear and having it regeared. I don't think the standard TJ D44 came with 4.10s from the factory(correct me if I'm wrong), except the Rubicon which is big bucks and hard to find used.
4.10s is good with 33s if doing lots of street driving, 4.56s with 33s are better offroad but run a higher RPM on the highway and can hurt fuel economy.
If you think you might go bigger than 33" then bite the bullet now and spend some coin on a HD rear end.
I agree with Clay, there is nothing wrong when a D35 for 31s or 33s as long as you watch the skinny pedal when wheeling. THAT IS THE BIG CAVEAT. I ran my D35 with an ARB for serveral years on 31s and a couple on 33s with 4.10s and no issues. I am still running 4.10s with the 4.0L and it is a little sluggish on the highway for 5th gear, but you can still use 5th gear. I would say as long as the axles are in good shape, then go for the 4.10s.
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Maybe i misread it. i THOUGHT he already has a 30/35 combo and he wants to swap a 30/35 combo in because it came with 4.10's?
Just seems like a waste of time and money.
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Maybe i misread it. i THOUGHT he already has a 30/35 combo and he wants to swap a 30/35 combo in because it came with 4.10's?
Just seems like a waste of time and money.
That is correct, but he would be going from 3.07s to 4.10s which would make a HUGE difference
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I've been bagging the hell out of my D35 for years running 33" tires on my TJ and haven't had any problems at all, you guys have to quit giving the D35 such a bad rap. I think it all comes down to the driver, knowing not to mash the skinny peddle while in the rocks unless your driving a buggy is just common sense.
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I've been bagging the hell out of my D35 for years running 33" tires on my TJ and haven't had any problems at all, you guys have to quit giving the D35 such a bad rap. I think it all comes down to the driver, knowing not to mash the skinny peddle while in the rocks unless your driving a buggy is just common sense.
Bagging a jeep is a matter of perception. My perception of bagging a stock 35 on 33's mean inevitable failure. Yours obviously is different.
There are people here that have seen a d35 break on a DIRT ledge no less then 3 times in a row, with three different drivers.
Conversly, some of those guys saw my wife hit that same dirt ledge almost 20 times with all 4 wheels off the ground and not break her trussed super 35 on beadlocked 33's at 4 psi.
I can take you up a line in mclean that if you are locked front and back, running 5 psi or less, I will garruntee that you have no better then a 50/50 chance of busting a stock d35.
35's can be modded to be fairly reliable while locked on 33-35's, but it does take money, and without that money they are very unreliable offroad.
The more tire and or traction you add to them without modifying them accordingly, just adds to the risk you being "that guy" we've helped off the trail so many times.
In short, no, we dont have stop giving the 35 a bad rap. There are more then enough incidents within this club to substanciate what the guys are saying about the positives and negatives of the d35.
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Thanks for the great info guys. I would upgrade to 44s right off the bat if my financial situation permitted it and if I knew this was something I would be willing to just empty every pocket into. But at this point I am still just getting started, and don't get me wrong have enjoyed every minute, but at this point I need to be making more money and get more experience with my vehicle (how i drive and and how to fix it) before I do any huge upgrades like that.
And yes I am swapping out 30/35 for a 30/35, and one option is a fraction of what it would cost to re-gear my currrent axles and the other option is about the same price but I would be gaining lockers as well. Plus in both cases, as mentioned, I would be have tones of spare parts so if something does break I wont be stuck.
I do have another questions though, this time regarding brakes. If I go to 33s i've heard the stock brakes are sufficient. Whats the consensus on this? I would like to stay with a 15" rim so I don't lose to much clearance. What options do I have in this case for improving my stopping power with the bigger tires?
Thanks again!
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... I do have another questions though, this time regarding brakes....
That's a good question. In the summer I run 33's and I find the brakes... could be better. I have read on NAXJA that the front disc brakes on a D30 can be upgraded using WJ (Grand Cherokee) calipers (that are two piston) and rotors (which are larger). As for rear brakes, the only real option is to upgrade from drums to discs. There are disc brake kits that you can get to convert your rear axle. However if you're also considering an axle upgrade and/or gears, you could just grab a stronger rear axle from the junkyard that already has disc brakes (eg Ford 8.8 ) and that kills two birds with one stone.
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I do have another questions though, this time regarding brakes. If I go to 33s i've heard the stock brakes are sufficient. Whats the consensus on this? I would like to stay with a 15" rim so I don't lose to much clearance. What options do I have in this case for improving my stopping power with the bigger tires?
Thanks again!
I don't think you will regret your decision. As for the brakes, I drove mine with 31s and 33s for several years and even pulled a 16' boat with mine. The brakes are decent but the main thing is you need to keep an eye on your drums because mud will eat the shoes very quickly and they loose their adjustment, so the fronts will be doing ALL the work. Now you could look at a performance pad like EBCs as an alternative.
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I run slotted rotors and HAWK pads. Definetly helps!
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Jrama, you are the man!
Used the calculator for my set up in the YJ....... gives me 90 kph at 1800 rpm
Saved me hours and hours of work.
Was using my gps for speed and my factory tach for rpm and getting 90 kph at 2800 rpm..... (tach is a way out)
Was going to drop in 3.55 axles, now just have to chase down other reasons for low gas mileage.
Again, thanks for the post!
Greg
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buy my dana 44's front and rear locked 5.13 gears Chromoly shafts . disc brakes front and rear .. direct bolt in to that you got plus ill include the wiring harness for the lockers and compresors for them as well 4500$
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Wait till I get a few months work in the patch....
I have an $1800 yj, $1600 tires $800 TJ trans and tcase, $300 sye kit, so $4500 axles would not be too far out of line.
Greg
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if your in the oil patch .. u wont have to wait .. your next pay will be 5000$ so ull have enough hahhaha