JK 4 door + 37s = new driveshaft(s)?
 

With all of the 4 door JK pics with 37s, I'm wondering who needed new driveshafts. If you didn't need a new driveshaft, which lift kit did you buy?

If you needed a new driveshaft, which one did you buy? How much did it set you back?

I'm planning on a 4" lift and 37s. If a new driveshaft or two is required, I'll add that to the list...

:confused: :thinking: :naw: :yup:

-a2kl

a2kl,

After all of the research that I have done I have concluded that on a 4" lift kit a front driveline would be a must and a rear driveline would be highly recommended. Keep in mind I am not speaking from experience but only countless hours of research. Good luck and post pics when complete.

Stupid Hurts! Drive it like you stole it:cool:

What immediate benefits would you gain from having a new driveshaft? If you aren't seriously wheeling, don't worry about it until it breaks. You're only saving money if it doesn't. Now if you wheel away from civilization on a regular basis, then yes it may be worth it. MOstly it will just wear out quicker.

If you are planning on running 37's, especially with stock gearing, I would highly recommend changing drive shafts. The load of the new taller tire is going to put a greater strain on the driveshaft. The strength of the factory drive shaft is decieving. It has a huge outer tube with a new slip yoke design, but it tapers down to about an inch at the all new small True cv joints.
I personally recommend regearing and changing drivelines . I am running 5.13 Superior Gears and J.E Reel drivelines with 1350 u-joints. By changing the gear ratio, it lightens the load on the drive shaft and gives you a power boost. With the 1350 u joints, It makes your driveshaft very strong, limiting your chances of breaking.

I am planing on changing the drive lines when I step up to 37's so I'm not knocking that. but EVO can you give a little more about your last comment about "especially with stock gearing " I don't think that what gears you run it the axles have anything to do with if you run a "CV" type driveline or a "U-joint" style. the only problem that has ever been mentioned about the "CV"(stock) style driveline's are the angles wearing out the boot which holds the grease thus causing the goint to fail due to lack of lubrication....

I am more concered about the stenth of the stock drive shafts and CV . If it is just a lubication issue we could probly find another cv boot that could hold up to the greater angle.

I think that is the question....how strong are they ?? I don't think anyone has broken one yet and there seem to be alot of JK's running 37's....

DHO
They could last forever driving to the store and back or normal street driving. I personally did not want to take the chance of breaking down on rough trails like Sledge Hammer with a part that can't be picked up at the local parts store. I believe the 1350 u joints are far superior to the stock cv.

yea I'm with you on that with out a doubt. like I said earlier I'll be running U-joint style shafts myself (will probably build and not buy), even if the stock setup is strong it's not the "if I break" its the "when I brake" factor and if you don't have a extra complete drive line as a back up then your going to be kinda screwed with the stock setup...

so for the original poster of this thread if you want to take the chance then take it but from what I have heard the ONLY reason that the lift companys are saying that you need a new drive line is because of the angle of the driveline wearing out the boot which causes failure of the joint, it's not a strength issue nor is it a binding issue....

I would rather get better drivelines now than wait till they break because if you have ever experienced a driveline breaking you know it is not the only thing that can break along with it like your ring and pinion or spider gears it can really get costly I would rather do preventative maintanance now better than waiting for it to break and another reason to go with a U-joint driveline would be: when your cv-joint breaks were are you going to find a replacement even if your in a town it is going to be hard to find with a u-joint driveline you just have to go to any car parts store or even hardware store and can get a new U-joint

I agree that upgrading prior to breakage is a good idea, but I've been looking at the Reel 1310 OEM replacement driveshafts. With this setup I could carry my stock shafts as spares, and replace them quickly on the trail without many tools if I broke a u-joint. Does anyone know of an advantage to changing yokes if you are sticking with the 1310's? It seems to me that with the stock round flanges, you would not be risking breaking as quickly if your yoke was on a rock while the shaft was turning.

how much do they cost???

I'm interested to see where this goes. If a U-joint snaps it is just a trip to the parts store...

but interestingly enough, JP Magazine ran an article on U-joint and stub axle stress testing. During the test, a maker of a replacement birfield unit for Toyotas placed one of his aftermarket units in the machine and it dominated everything else in the test, including the D-60 joints and stub axles. (the name of the manufacturer escapes me at the moment.. and the mag isnt handy.. but he's a regular member on Pirates....) Their prime advantage over standard U-joints is that they maintain their max strength all the way to their max twist or travel.. where with u-joints, the more angle you put on em, the weaker they are. granted these were axle shafts, and not driveshafts... but the principle is the same.

Kind of interesting, but I'm like the next guy... I dont want to be stuck in the middle of nowhere with busted stuff. Not wishing bad things on people, but it takes people breaking stuff for us all to learn how far you can push it.

I think you are referring to the Longfield Toyota axles. And yes, they are very strong. The Reel 1310 OEM replacement shafts are listed to $385.

$385 is for the rear only for front and rear list is $1126 that is from www.northridge4x4.com
I am going to have a very reputable local shop build mine for me they have done work for me in the past on other jeeps and have done excellent work
where ever you get your drivelines from I think the peace of mind that if you break it you can get replacement parts for it anywhere and fix it is worth what ever price you pay

WOW! I hadn't noticed that. I figured that $385 would get you either one you wanted. That means that the front is $741??? They're crazy!:mad:

I just looked at their site again and it is not calculating the prices correctly. 1310 CV's are $355 ea, 1350 CV HD's are $510 and $525 ea, and the 1310 CV OEM's are $385 ea. For some reason they have their site adding the cost of the base CV to the cost of each one.:yup:

oh that is a much more reasonable price
is that some sort of core charge maybe?

If I had to guess I would say that their web designer goofed. I have never heard of a core charge for a driveshaft, and they aren't re-using any of the old parts.

OK are you talking about front axle CV's or driveshaft joints now......the original discussion is on Driveshafts and now we are on an axle tangent....LOL

Hmm...

So judging by the responses so far, it looks like the silent majority are not upgrading their driveshafts when going to 37s - unless the cost was so high they don't even want to talk about it! ;)

I suppose I could put the thing in the air, drop the shaft first, and make a judgement call on my own as to the expected life of the factory boots. I've seen some pics of people doing what looks like serious offroading on 37s, and they haven't posted info about upgrading their driveshafts. So that's a check in the 'do nothing' column. However, I don't want to be stuck somewhere google maps can't find, and dry my tears with a busted boot.

I guess the other thought was that a _longer_ driveshaft or two might be needed for a lift of 4" or more. Again, I haven't heard anyone say longer 'shafts are needed, so I'm taking that as a "no". Since I'm new to some of this, I'm not entirely sure how longer control arms make up for a more diagonal driveshaft position (which would bring the axle closer to the center of the vehicle). I'm not big on buying a bunch of parts, closing my eyes, and hoping for the best - unless it's not my ride! :rotflmao1:

still learnding,

-a2kl

The only reason I see if putting new driveshafts on would be for a longer slip yoke. A replacement shaft will have the same u-joints that are in the now so whats the point. The rear shaft is long enough that a special CV shaft isn't nessesary.

Thanks, but we are not on a tangent. Those are driveshafts.

Because of the way the suspension works, there actually isn't that much of a need for a longer shaft unless significant geometry changes are made. When the axles drop down, they swing toward the center of the vehicle. This is different from leaf springs with shackles on the outer ends, which almost always make a longer shaft necessary.

just to clearify what I am talking about
http://project-jk.com/gallery2/main....serialNumber=2
the top on is a u-joint something you can find any where the bottom is a cv-joint
I have 4" lift and running 37"s and I am going to upgrade

Bonedigger- be sure to post what you get. I will be upgrading mine as $ permits... Especially since I have already torn the front boot. If no one has noticed yet, the front driveshaft u-joint doesn't have clips. The joint is pressed in and the yoke "punched" to retain it.

that is what the guys at six states called a fixed u-joint and I will be replacing that also

evolution guy's= always right!!!
 

If the guy's from Evolution are giving advise...take it. These guys know their shit and they know from experience. They've been there and done that. Thanks for your feedback fellas! You have definitely helped me with my Project JK over the phone. Big props!!!

What???
 

Wrong... 4" inches or more means YES! There are two words being thrown around alot "Recommended" or "Required". They are being thrown around lose-ly. There is a big F-ing difference. Im trying hard not to sound like a dick. But speaking from experience those two word have screwed me in the last 3 weeks!!! I have a 5" Skyjacker Lift, 1 Inch M.O.R.E. Body lift and im running 37's. Also I have replaced both drive shafts with JE Reels 1350 set for front and rear. Why invest all this money into a brand new vehicle and do it half-ass. Because in the long run you will do more damage to other parts and will eventually cost you more money. If you want to cut costs for now... than dont by the bumper, winch, seat covers, etc... spend the money where it counts. If you want the real scoop call the guys at Evolution. Who am I? No one special! But think about it... its your driveline your talking about. You don't have shit without it!!!

can i use my free spin?
 

Many interesting things in this quote:
1. There's no right or wrong answer for posts in this thread. I'm just asking what have people done, and my reply was based on the responses so far. Whether what they have done is right or wrong isn't up for debate (at least not in this thread)

2. You mention two words being thrown around, and then you throw them around yourself, without mentioning which word is the correct word, in your experience. Yes, you did the upgrade. But w/o the upgrade, were putting 37s on your machine impossible? If so, that would be helpful. If not, that would be helpful too. Even if you (or an expert) don't advise going a certain route. It sounds like not upgrading almost bit you in the butt - why? Did you order everything else and then find out it wouldn't work w/o driveshafts? Something else? If it's been a 3 week ordeal, I'd like to hear the story.

3. You quoted my quote, which already stated that people with 37s on right now have yet to post "yes, I had to upgrade, impossible to do 37s w/o driveshaft upgrades, and they cost me $x" - yet you seem to have 37s, but don't really answer these questions for the thread. I know you DID upgrade your driveshafts, but the two important questions are left unanswered (saying that you didn't want to do something half-butted doesn't really count - everyone wants to do it all correctly, the question is whether or not you can ride around for a while (which seems to be yes) before EVENTUALLY getting driveshaft upgrades).

4. You are running a 5" suspension lift. It would be nice to know if 3", 4", or 5" or some other number is a number where _no one_ is using their factory driveshafts. That would be a telling stat too. Example: If someone is running a 2" lift, there's no need to upgrade your driveshafts UNLESS you want a more rugged set of parts. This is not the same issue originally posted in this thread. But I do know now from this thread that the "required/recommended" line is blurred at 4" because of the potential issues with the driveshaft angles and boots.

Yes, I agree, hearing from the Evolution dudes carries some weight - pun intended. But hearing from others (including you) who have been out on trails with or without new driveshafts is great too. Just trying to find out what everyone's doing, because I see lots of 37s, but not many people listing driveshafts on their list of "stuff they did" to their jeep.

-edit- I also see you have a 2 door jeep, so I'm not sure why you've posted a reply to this thread at all. :thinking: -edit-

-a2kl

I bought my Jeep to go "OFF-roading!" It is not a daily driver for me. So I am building it to stand up to anything. Im sure you can drive your Jeep back and forth to work and not have a problem with the stock drive shafts. All the experts that make the lifts say any lift over 4" require driveline modifications. Its not coming from me. So I believe the right answer is yes... you do need it. I didn't throw any words around. I did the upgrade because the people that designed my lift told me I would need it! It is similar to the TJ when it was required to use a slip yoke eliminator. Bottom line it is required by the lift companies. Call them and ask them. Ive done far more research than most on this forum. My knowledge is coming from me... its from the people who build this stuff for a living and they are damn good at it. I agree there are differences in some of the mods on a 2dr verses a 4dr. You sound like a smart guy. I know im not. You'll figure it out...see you on the trail... maybe! :naw:

Hey - no name calling! I'm not smart at all - you see I'm dumb enough to post to an online forum! :rotflmao1:

Anyways, the point of the thread was to find out the difference between "required" and "recommended" - the two words that are always tossed about, but never explicitly defined. For 2-door JKs, it sounds like everyone says new driveshafts are required for lifts of 4" or more. This seems to be a consensus born out of experience, and not just a sales pitch. For 4-door JKs, the answer has been less clear. The stock 'shaft with no lift must be fairly good - I've seen (and heard the crunch from) people doing stuff on rocks that I wouldn't do no matter what. I pretty much drove off the lot straight off-road to show off my JK to the in-laws - it's the easiest way to get to their house (and used to be the easiest excuse not to go visit! :D )

Yep, I expect to be on road just as much as off, if I choose to drive the JK when I get up in the morning. Eventually, I'll probably end up justifying all of the upgrades people are doing. It's just nice to hear if people aren't having problems right off the bat with 4" lifts and stock 'shafts. If this thread was filled with "Danger!! You will be the only noob on the trail like this" comments, then I would say thanks for that info too.

If you're in MI, I'm sure you'll see me and the JK covered in mud, somewhere

;)

-a2kl

From what I understand, on Unlimited, 4'' of lift didn't require any driveline mods to be driven on the road as there is not vibration due to the CV.

It's an other question if hard wheeling is intented. Then I will go with Evolution and say yes, you need better driveshaft just like any other 4by as there is no manufacturer that will overbuild a vehicule. They have a hard time doing $$$ and they cut on everything (just look at the hood try to fly when a 18 wheeler pass).

I think that is what we all have to know.

If someone can only put those driveshaft on a test versus other one that we know, then we will be sure of their strenght.

As for upgraded Birfield, it's been over 10 years that they try to mahke it better and better, that's probably why they have so great result. If someone take the same time on Jk'ones, then this will be a way to go.


Wish it help

CV vs u-joint
 

Been an engineer for some time. Not sure where these comments are coming from but here is what I can tell you. CV joints are strong. In fact, they are stronger than U-joints. CV joints can provide a greater range of mobility than a U-Joint without vibrations. While u-joints may look beefier, they are only as strong as the tear-out cross section which in fact is very small. Look at the hole where the u-joint is located. You can see how thin its at that point. While the load is one forth at that point, its still the weak point and is governed the shear max for that material. CV joints have a solid shaft that is significantly thicker. While they are still governed by shear max... there is more opportunity to expand the diameter, hence increasing its strength.

That being said, I cannot tell you how strong how strong of a load either one can handle with out looking at their specs. But, what I can say is that don't underestimate the strength of that CV drive shaft. Considering that DC beefed but the U-joints on the front axle, I would bet that the driveshaft is stronger than most of giving it credit for.