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-   -   2012 Rubicon and LSD (http://www.wranglerforum.com/f274/2012-rubicon-and-lsd-115943.html)

Rockyroad816 10-03-2011 05:21 PM

2012 Rubicon and LSD
 
I seen the threads on the Rubicon and LSD and I couldn't determine if the Rubicon came with LSD or it was a option.

I went on the Jeep "Build your own" and I tried to price of a Sahara with LSD and it was there as a option . However when I priced the Rubicon - LSD was not available as a option :confused: .

Is this Rubicon the standard equipment the LSD?

4:1 Rock-Trac Part-Time 4WD System
Tru-Lok Electronic Locking Frnt/Rear Differentials

From the Jeep Jeep - 4x4 Basics - How Jeep 4x4 Systems Work - 4WD SUVs

glowingghoul 10-03-2011 05:26 PM

No mechanical LSD on the Rubicon. The Brake Lock Differential (BLD) mimics the funtion of an LSD pretty effectively by using individual brakes to transfer torque to the other side of the axle.

I think you'll find most people have no issue with the Rubi in snow or rain, though the BLD seems to cause the rear brake pads to wear out before the front, from what I've heard.

rics1997 10-03-2011 05:36 PM

Yes the Rubi has a LSD when not locked in the rear diff. It isn't the same as the Sport/Sahara LSD option which is clutch operated, Rubis are not.

Rockyroad816 10-03-2011 06:18 PM

The reason I was asking is my 2009 Jeep Commander has the Quadra-Trac I full time 4wd which is great in snowy light slush 1 - 3 inches we get in SW Ohio.

When I test drove yesterday a Sahara yesterday the salesman made a point of telling me I couldn't leave the Sahara in 4wd hi like my Commander, which is in full time 4wd unless it was wet or slippery. He suggested the LSD rather than just the single rear traction. I am thinking LSD would help the snowy slippery patches . Or make a better transition from 2 wd drive to 4 wd on slippery hills.




mathjak 10-03-2011 06:32 PM

after the weak lsd in my xterra couldnt make it up a 3 ft square of slush and ice in our driveway without going into 4x4 i decided not to waste money on another factory lsd when i got my new 2012 sahara.

XJ Knight 10-03-2011 06:35 PM

Did Jeep upgrade there rear lsd's from past model jeeps? I know in past jeep models the lsd's were know to wear out eventually and become ineffective but Jeep could have fixed that by now.. If they haven't, Im sure someone will anwser the lsd wear out question for you.. but if it's me and they haven't changed them then I would get one with a open rear and just get a detroit tru trac for the rear if you want a lsd. I know and trust the detroit tru trac. Jeeps rear lsd I am yet to hear of them lasting the life of the jeep

MTH 10-03-2011 08:07 PM

Pretty sure the JK rubi does not--and cannot--come with an LSD. It's an open diff when not locked.

2012-Rubicon 10-03-2011 08:09 PM

Quote:

Originally Posted by MTH
The JK rubi does not--and cannot--come with an LSD. It's an open diff when not locked.

Care to explain? (dumb)

MTH 10-03-2011 08:22 PM

Quote:

Originally Posted by 2012-Rubicon

Care to explain? (dumb)

Sure. It's not an option. Can't order it. No choice.

Your diffs are either locked, or open, end of story. That is supplemented by the aforementioned "brake lock differential" that uses traction control to apply the brakes and simulate an LSD when your diffs aren't locked.

2012-Rubicon 10-03-2011 08:26 PM

Quote:

Originally Posted by MTH

Sure. It's not an option. Can't order it. No choice.

Your diffs are either locked, or open, end of story. That is supplemented by the aforementioned "brake lock differential" that uses traction control to apply the brakes and simulate an LSD when your diffs aren't locked.

Right ok Gotcha, I thought you meant like couldn't put one in period. Not that I want to was just curious. Thanks!

MTH 10-03-2011 08:35 PM

At least that's how I understand it. TJ Rubis came with diffs that were either locked or LSD, but my understanding is that's not the case for the JK. There are aftermarket systems that are both.

JIMBOX 10-03-2011 09:00 PM

:thumb:---BINGO--


Quote:

Originally Posted by MTH (Post 1624974)
Pretty sure the JK rubi does not--and cannot--come with an LSD. It's an open diff when not locked.

Righton
Quote:

Originally Posted by 2012-Rubicon (Post 1624986)
Care to explain? (dumb)

No room for lsd plates/clutchs--full of elock mech.

Quote:

Originally Posted by MTH (Post 1625045)
Sure. It's not an option. Can't order it. No choice.

Your diffs are either locked, or open, end of story. That is supplemented by the aforementioned "brake lock differential" that uses traction control to apply the brakes and simulate an LSD when your diffs aren't locked.

--BINGO-

Quote:

Originally Posted by 2012-Rubicon (Post 1625065)
Right ok Gotcha, I thought you meant like couldn't put one in period. Not that I want to was just curious. Thanks!

Right, can't be added

Quote:

Originally Posted by MTH (Post 1625100)
At least that's how I understand it. TJ Rubis came with diffs that were either locked or LSD, but my understanding is that's not the case for the JK. There are aftermarket systems that are both.

But not the 07/11 Rubi /w elockers

:dance::rofl: JIMBO

2012-Rubicon 10-03-2011 09:17 PM

On that note,do the e-lockers work as wells as say ARB air lockers? The only vehicles I have ever driven off road were a 2005 jeep and a land rover defender(I think) both had ARB air lockers and those were great!

XJ Knight 10-03-2011 09:19 PM

yep same idea.. different form of activation and engagment.

panthermark 10-03-2011 09:47 PM

If I remember correctly, the TJ Rubi's from 03-06 had air lockers AND a gear operated LSD in the rear. But the JK Rubi's have e-lockers and the BSD in the rear. Current JK Rubi's do not have a true mechanical LSD.

3JKs1H1 10-03-2011 11:09 PM

Quite a few choices when it comes to lockers. Detroit variants are full-time mechanical lockers that differentiate. That means they are always on and allow the outer wheel (when in a turn) to turn faster than the inner wheel. So unlike an open diff or LSD, all tires are powered. The downside is their handling - in the rear they have a habit of wanting to fishtail when you suddenly let off the gas. If you city and highway drive, and not in deep snow or mud, they probably aren't the best choice.

An Auburn or Eaton (probably ARB), creates a solid axle when locked. The Rubi has this. Unlocked, It mostly has better on road behavior, but creates a solid axle when engaged. So in mud, sand, or snow, - all tires are moving at the same clip.

If it were me, I'd probably shy away from an ARB. Look for an auburn. eaton, or detroit - where you only ned 12volts for engagement. No Compressor and lines required.

Discalimer, I hvae installed 3 detroits in Hummer H1's. I've then added 2 Auburns and couldn't been happier. The originals with thir LSD can follow on thir own accord,

panthermark 10-04-2011 07:47 AM

Wrangler JK TFS Electric Locker
Overview: When Jeep upgraded the Wrangler line to the '07-up JK platform, the old pneumatically-actuated lockers of the TJ Rubicons got the heave-ho in favor of the new electronically-actuated selectable lockers. Although they only fit Rubicon Dana 44 housings, the TFS Dana 44 Rubicon lockers markedly simplify the installation of Rubicon axles in a non-stock application, requiring only a switched source of 12V power to actuate.

Street:
Hey, when it's off it's an open diff. No drawbacks here.

Off-road: To be somewhat picky, we've found the JK Rubicon axles sometimes need to be locked 20-30 feet before you need them, rather than when you're already stuck. When locked, they effectively function as a spool, offering uncompromising traction in any and all terrain. That is, as long as your tires are up to the task.

Good: It's got millions of dollars in factory-funded research and development behind it. They just work.

Bad: They only work in JK Rubicon Dana 44 axle assemblies, so you can't just plunk one in your '76 Wagoneer front axle.


------------------

Trac-Lok
Overview: The Trac-Lok is the OEM limited slip differential offered in many vehicles-from early CJs from the mid-'70s up through XJs and some TJs. It uses stacks of friction discs that hold the spider gears from differentiating until enough torque is generated by the shafts to let them spin.

Street:
You'll think you're driving an open diff. The Trac-Lok is largely unnoticeable.

Off-road:
You'll think you're driving an open diff. The Trac-Lok is largely unnoticeable. Unless it's new from the factory, don't expect anything but poor performance off-road from a Trac-Lok.

Good: It probably came in your Jeep from the factory. The unit can be rebuilt at home.

Bad: They require gear oil with a friction modifier and have wearable clutches inside. If you're planning on adding a lunchbox locker, you'll need to order a special application that will work with the clutch disc recess in the case. The recess inside of the case makes it slightly weaker than a standard open diff case. It's difficult to weld into a spool if that's your thing. Basically, they don't work well, so don't waste your money. You're better off with an open diff.


---------------


Rubicon TJ TFS Air Locker

Overview: The good news is that if you bought an '03-'06 Wrangler Rubicon, you got a pair of these for free. The Rubicon's pneumatically-operated TFS lockers featured an open/spool configuration in the front and a gear-driven limited slip/spool configuration in the rear.

Street:


See Truetrac listing for more information.

Off-road:

The units are unintrusive when unlocked and offer spool-like traction when locked. Aside from very few compressor or air line troubles caused by trail debris, the lockers themselves are extremely durable and most of the time are quick to lock or unlock. Off-road, they've proven themselves for use with tires up to and over 37-inches in diameter with no ill effects.

Good: Long-lived durability, and exceptional off-road performance.

Bad: They're not exactly cheap or very easy to come by unless you're starting with a Rubicon or a set of replacement axle housings. Also, the lockers require a very low-pressure (3-5psi) source of air or you can blow out internal components.


-------------------

Detroit Truetrac
Overview: The Truetrac is a gear-driven limited slip that requires no special friction modifiers to operate. That means that the bozo at the Qwikee Lube can't destroy your spendy limited slip by putting the wrong oil in. Under power, torque is sent to both tires unless there's an excessive amount of resistance on one.

Street:
The Truetrac is very unobtrusive on the street. When gassed in a corner or turn, you may feel the slightest pull, but there's no jerking or violent engagement of any sort. When under heavy throttle in a turn, the inside tire will bark a little, but not under normal driving conditions. Turning radius and tight maneuvers are totally unaffected.

Off-road:
The Truetrac offers near locker-like traction in all but the gnarliest terrain. We've found that modulating the brakes a bit can help keep one tire from spinning when the suspension is crossed up. You can't drive as elegantly in the rocks as you can with a spool or locker, but you'll have to work pretty hard to get stuck. In loose dirt twisties where you're lifting a tire, a Truetrac will almost always get you through.

Good: Great traction on- and off-road and can use straight 90W gear oil. They're moderately priced and great for front and rear applications.

Bad: There are a lot of little parts inside, so it's not as strong as most full-case lockers. Also, it doesn't offer as much traction as a locker or spool, and you may slightly notice it operating during some street driving.

----






oilwell1415 10-04-2011 08:31 AM

Quote:

Originally Posted by mathjak (Post 1624676)
after the weak lsd in my xterra couldnt make it up a 3 ft square of slush and ice in our driveway without going into 4x4 i decided not to waste money on another factory lsd when i got my new 2012 sahara.

That is not the fault of the LSD.

Quote:

Originally Posted by XJ Knight (Post 1624684)
Did Jeep upgrade there rear lsd's from past model jeeps? I know in past jeep models the lsd's were know to wear out eventually and become ineffective but Jeep could have fixed that by now.. If they haven't, Im sure someone will anwser the lsd wear out question for you.. but if it's me and they haven't changed them then I would get one with a open rear and just get a detroit tru trac for the rear if you want a lsd. I know and trust the detroit tru trac. Jeeps rear lsd I am yet to hear of them lasting the life of the jeep

There isn't a friction type LSD out there that doesn't wear out eventually. They all degrade with time and need rebuilt. Most are showing signs of wear within 20k-30k and need the clutches replaces by 50k miles. This is not a big deal most of the time. The clutches for my 8.8 cost $50 and took half an hour to install. Conversely, the clutches for my 9.75 are over $100, took several hours, and were a vocabulary expanding linguistic adventure to install. The poor neighbor kids are likely scarred for life, or at least a little perplexed. I understand the Jeep is more like the latter, but haven't yet had the pleasure of finding out.

JIMBOX 10-04-2011 08:34 AM

:D Very good panther, outstanding presentation, any/all that want lockers can use that for good info !!

I can only say that the elockers are great, but can be cranky---and they have many restrictions, just like a wife !

:dance::rofl: JIMBO

JeepinAl 10-04-2011 10:06 AM

Quote:

Originally Posted by MTH (Post 1625045)
Sure. It's not an option. Can't order it. No choice.

Your diffs are either locked, or open, end of story. That is supplemented by the aforementioned "brake lock differential" that uses traction control to apply the brakes and simulate an LSD when your diffs aren't locked.

I'm in the same thought "boat" you are, however...


2012 Jeep Wrangler Unlimited 4WD Rubicon SUV in Charlotte, NC

Options

SAFETY AND SECURITY


Brake assistIgnition disableElectronic stabilityDual front impact airbagsABS brakesPanic alarmOccupant sensing airbagSecurity systemDual front side impact airbags4 wheel disc brakesTraction controlIntegrated roll-over protection↑ to top Tech Specs

POWERTRAINEngine liters: 3.6Torque: 260 lb.-ft. @ 4,800RPMLimited slip differentialCylinder configuration: V-6Variable valve controlFuel economy highway: 21mpgSequential multi-point fuel injectionNumber of valves: 24Recommended fuel: flexibleHorsepower: 285hp @ 6,400RPMFuel tank capacity: 22.5gal.Fuel economy city: 16mpgDrive type: four-wheelEngine location: front


Wouldn't be the first time a car manufacturer had a different "definition" of an option

MTH 10-04-2011 10:10 AM

^^The Rubi does have "electronic stability." I think they just copied the wrong description as to the LSD or the marketing materials are wrong.

oilwell1415 10-04-2011 10:11 AM

Quote:

Originally Posted by MTH (Post 1626609)
^^The Rubi does have "electronic stability." I think they just copied the wrong description as to the LSD or the marketing materials are wrong.

I can't imagine that Jeep would botch either of those for the 2012 Wranglers. :whistling:

Rockyroad816 10-04-2011 03:10 PM

I don't want to beat a dead horse on this LSD thing. But, I found this on locking differential and differential lock are not the same
I don't know jack about this topic. So does this make sense ?


"If you have to decide whether to get a "locking differential" aka limited slip (LS), if available as an option on your new truck, I would recommend getting it, because it is still better than not having anything at all."



"locking differential and differential lock are not the same thing!

Only few vehicles in the US are offered stock with front and rear differential locks: Dodge Powerwagon, Hummer H2 + H3, Jeep Wrangler Rubicon, Mercedes G500.

On some models a rear differential lock is optional: Porsche Cayenne, VW Touareg, some Mitsubishi, some Toyota.
Other terms used for differential locks are: locker, diff locks, diff lockers, differential lockers

Unfortunately,
limited slip differentials (LS), available as options for many 4x4 in the US are offered by sales people as "locking differentials". A confusing term because nothing on these differentials is LOCKING. They are by far inferior to a differential that is truly (manually or automatically) lockable.
If you have to decide whether to get a "locking differential" aka limited slip (LS), if available as an option on your new truck, I would recommend getting it, because it is still better than not having anything at all.

To repeat: "locking differentials" are limited slip differentials that are not to be confused with differential lock!

Differential lock = differential locker = diff lock = diff locker = locker


It seems to me, that manufacturers and dealers prefer to use the term "locking differential" over the correct term "limited slip differential" because it sounds more like the real thing - even though it is not. Is this already consumer fraud?


Now here is a twist to the locking differential story: When Chevy advertises its trucks with an optional rear locking differential - it indeed is a differential that locks up (automatically). In the 80's it was sold as a Gov-Lok for a while named Command-Traxx and is available in some Chevy trucks as G80 option. It is not manually activated as in Dodge, Jeep and Mercedes - it locks up automatically. It is a hybrid of a clutch type limited slip unit combined with a flyweight governor that is able to lock up 100%.


In addition to factory installed diff locks, there are several aftermarket options to add a differential lock to front and rear axles.
ARB Air Locker, Detroit Locker, Eaton Locker are probably the best known. Recently we saw some newcomers like the OX Locker which seems like a copy of a long know German Schwarz locker to me.


panthermark 10-04-2011 03:39 PM

Quote:

Originally Posted by JeepinAl (Post 1626600)
I'm in the same thought "boat" you are, however...


2012 Jeep Wrangler Unlimited 4WD Rubicon SUV in Charlotte, NC

Options

SAFETY AND SECURITY


Brake assistIgnition disableElectronic stabilityDual front impact airbagsABS brakesPanic alarmOccupant sensing airbagSecurity systemDual front side impact airbags4 wheel disc brakesTraction controlIntegrated roll-over protection↑ to top Tech Specs

POWERTRAINEngine liters: 3.6Torque: 260 lb.-ft. @ 4,800RPMLimited slip differentialCylinder configuration: V-6Variable valve controlFuel economy highway: 21mpgSequential multi-point fuel injectionNumber of valves: 24Recommended fuel: flexibleHorsepower: 285hp @ 6,400RPMFuel tank capacity: 22.5gal.Fuel economy city: 16mpgDrive type: four-wheelEngine location: front


Wouldn't be the first time a car manufacturer had a different "definition" of an option

Jeep literature.....:nonono:

oilwell1415 10-04-2011 03:41 PM

I think that talked all the way around the circle and still didn't clear anything up. Here is what the types mentioned are:

Limited slip differential: This uses some form of friction or mechanical force to increase the torque required to make one tire turn at a different rate than the other. These are never truly locked together and some slip is always possible. The Gov-Lok is in this category. I am not familiar with the Command Traxx.

Locking differential: This is a differential assembly that automatically locks itself together allowing zero slippage from one tire to the other when needed. When one tire needs to turn at a different rate than the other for cornering it automatically unlocks to allow the turn to happen as it should.

Differential lock: This is a manually actuated function that physcally locks the two wheels together. It does not slip and does not disengage for turns unless you manually unlock it.

panthermark 10-04-2011 04:03 PM

Quote:

Originally Posted by oilwell1415 (Post 1627356)
I think that talked all the way around the circle and still didn't clear anything up. Here is what the types mentioned are:

Limited slip differential: This uses some form of friction or mechanical force to increase the torque required to make one tire turn at a different rate than the other. These are never truly locked together and some slip is always possible. The Gov-Lok is in this category. I am not familiar with the Command Traxx.

Locking differential: This is a differential assembly that automatically locks itself together allowing zero slippage from one tire to the other when needed. When one tire needs to turn at a different rate than the other for cornering it automatically unlocks to allow the turn to happen as it should.

Differential lock: This is a manually actuated function that physcally locks the two wheels together. It does not slip and does not disengage for turns unless you manually unlock it.

So would you consider "BLD" limited slip?

oilwell1415 10-04-2011 04:46 PM

Quote:

Originally Posted by panthermark (Post 1627399)
So would you consider "BLD" limited slip?

BLD has nothing to do with the differential. It's none of the above.

glowingghoul 10-04-2011 05:45 PM

Quote:

Originally Posted by oilwell1415 (Post 1627498)
BLD has nothing to do with the differential. It's none of the above.

It has nothing to do with the differential, but serves the same function as an LSD, albeit using sensors, computers, and brakes, rather than a mechanical device.

oilwell1415 10-05-2011 08:01 AM

Quote:

Originally Posted by glowingghoul (Post 1627637)
It has nothing to do with the differential, but serves the same function as an LSD, albeit using sensors, computers, and brakes, rather than a mechanical device.

So what's your point? It isn't a type of differential, which is what the thread is about. It's a glorified traction control system which is present on most vehicles made today.

panthermark 10-05-2011 08:18 AM

^But given your definition:
Limited slip differential: This uses some form of friction or mechanical force to increase the torque required to make one tire turn at a different rate than the other. These are never truly locked together and some slip is always possible.

BLD does fit the term....well...kind off. Not a pumpkin...but serves the same purpose....almost.

But again, the earlier Rubi info also says the recommended fuel is flexible, and that it gets 21 mpg....for an Unlimited.....which is incorrect. Can't trust Chrysler....


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