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Topic Review (Newest First)
11-28-2012 02:55 PM
rich67 Great thread indeed. Glad I got the option now.
10-17-2012 11:49 AM
floodwaker This thread was a huge help. I had ordered my Sahara last week to be built but had left off the LSD. I just called the dealer and added it. A VIN hadn't been assigned yet, so I was able to make the change! Now I just have to hurry up and wait.

Thanks for all the great info!
09-28-2012 05:40 PM
BenDiem ^^^Gents,

Thanks so much for your valuable time and efforts!

I've finally seen the light. Your posts confirmed to me that for a measly $295, the benefit of DSA (mall crawler/living in the Midwest w/lots of rain & occasional snow) outweighs the option of trying to save what little money $295 is over a three (3) year loan.

Tks/Great Forum!

BB
09-28-2012 05:10 PM
panthermark According to the BLD video (post #9), Trac-Lok can has a bias ratio of "up to 2.7"....that is at the 3:23 mark.

Take it for what is worth because the video also said that a Jeep with BLD can navigate almost any situation a similar vehicle with lockers can do.

I would love an Eaton LSD over the factory LSD, but for $295 MSRP on a mall crawler, the factory unit will be fine.
09-28-2012 04:38 PM
Rooster76
Quote:
Originally Posted by oilwell1415 View Post
I understand that bias ratio applies to all LSD systems. The problem is that the numbers are at best theoretical. I have not been successful at explaining this with words, so let's throw some numbers at it. Let's say we have a Jeep rolling down the trail with an engine and gear ratio combination that supplies 10,000 ft-lbs of torque to the rear axle. This seems like a huge number, but is not far off the mark for one really working hard in 4L. Then one wheel on the rear axle loses half of its traction and is only able to apply 5,000 ft-lbs to the ground. If a diff had a 3:1 bias ratio that would mean that 15,000 ft-lbs are going to be sent to the tire with traction, but that can't happen because there isn't that much torque available in the first place. It will also be losing a ton of power to heat as the clutches slip which will further reduce the torque available to the other tire.

Speaking of the clutches slipping, it would seem from above that the more the low traction tire spun, the easier it would be to meet our mythical 3:1 bias ratio. Unfortunately, the force applied to the clutches is directly proportional to the load placed on the diff. If you have one wheel in the air with zero traction, there will be basically zero load on the diff and zero load on the spider gears. Zero load on the spider gears means that the only force acting on the clutches is what is provided by the preload spring which isn't enough to do anything on the trail. You could demonstrate this to yourself by driving up a steep hill with one tire on pavement and one tire on dirt. If the tire on dirt loses traction you stop moving up the hill. If the diff sent 3 times more torque to the other side you would keep going, but you don't. You still sit there stopped.
BIAS RATIO IS THE MAX
The way that I understand it is that the Bias Ratio is the absolute maximum amount of toque that can be given to the tire with traction. Basically if one tire has little (but some) traction. When described in "The Four Wheelers Bible" (Link to that section Four-Wheeler's Bible - Jim Allen - Google Books) he uses the words, "can", and "will allow" vs "will give".

WHEEL IN THE AIR
With a wheel in the air LSD sucks and lockers are awesome. Like you stated preload isn't going to do a whole lot, and it puts more wear on the clutch plates (because of the preload). To overcome this it's a good idea to disconnect your front sway bars (they make quick disco's= disconnects that make it easier) to keep the wheels on the ground. Also you can apply a bit of break, and/or parking break to help get extra "artificial" traction.

3:1 BIAS RATIO
The 3:1 bias Ratio I brought up was talking about the after market eaton truetrac. That is from trusting the quote in post 6. The guy seems to know what he is talking about. It's hard to find solid numbers about Trac-Lok.
Quote:
Dynatrac- http://www.jk-adventure.com/JKA/modi...629/#post21571
....The factory Trac Loc has a bias ratio of between 1.6 and 2.0. Using the 2.0 ratio as an example, this means that in a low traction situation 2x the torque of the bad side will be transferred to the side with traction. In the case of our example where 30 lbs. of torque was enough to spin the tire, 2x or 60 lbs. of torque will be transferred to the other side. Depending on the situation, 60 lbs. of torque may or may not provide enough push to move the vehicle. A better LSD with more bias has a better chance of moving the vehicle. A Truetrac has nearly a 3-1 bias ratio......
If we take these numbers as reference and convert them into (max) locking percentage you would get.
Eaton truetrac locking %= 50
factory Trac-Lok would have a locking % of 25

At some point the numbers are BS I suppose, and it comes down to if it works or not. The factory trac-lok is better than not having it. The eaton truetrac aftermarket lsd option is better than that. Depending on how you want to use Jeep, on road vs off, lockers might be a good choice.
09-28-2012 02:55 PM
oilwell1415
Quote:
Originally Posted by Rooster76 View Post
Here is a link that goes to the section on LSD from "Four-Wheeler's Bible" I wish I would have found it sooner and just posted this link.
LINK->Four-Wheeler's Bible - Jim Allen - Google Books

Bias Ratio is a term that covers all LSD systems. So to that regard it doesn't really matter what LSD system was featured.
I understand that bias ratio applies to all LSD systems. The problem is that the numbers are at best theoretical. I have not been successful at explaining this with words, so let's throw some numbers at it. Let's say we have a Jeep rolling down the trail with an engine and gear ratio combination that supplies 10,000 ft-lbs of torque to the rear axle. This seems like a huge number, but is not far off the mark for one really working hard in 4L. Then one wheel on the rear axle loses half of its traction and is only able to apply 5,000 ft-lbs to the ground. If a diff had a 3:1 bias ratio that would mean that 15,000 ft-lbs are going to be sent to the tire with traction, but that can't happen because there isn't that much torque available in the first place. It will also be losing a ton of power to heat as the clutches slip which will further reduce the torque available to the other tire.

Speaking of the clutches slipping, it would seem from above that the more the low traction tire spun, the easier it would be to meet our mythical 3:1 bias ratio. Unfortunately, the force applied to the clutches is directly proportional to the load placed on the diff. If you have one wheel in the air with zero traction, there will be basically zero load on the diff and zero load on the spider gears. Zero load on the spider gears means that the only force acting on the clutches is what is provided by the preload spring which isn't enough to do anything on the trail. You could demonstrate this to yourself by driving up a steep hill with one tire on pavement and one tire on dirt. If the tire on dirt loses traction you stop moving up the hill. If the diff sent 3 times more torque to the other side you would keep going, but you don't. You still sit there stopped.
09-28-2012 01:17 PM
SilverSport
Quote:
Originally Posted by 12JKUR View Post
This is gonna take me a bit to digest.

What is #25 on the exploded view of the diff above?

How does the term "open diff" come to play, what is "open"?
#25 is for the Rubicon diff with the e-locker. It connects to the harness from inside the diff.
09-28-2012 01:07 PM
12JKUR
Quote:
Originally Posted by oilwell1415 View Post
Open means it is simply a regular differential. They call it that because there is an open hole in the middle of it where the guts of a limited slip or locker would be if it was one of those. It does nothing to force torque to the wheel with traction.
Perfect, thanks!

Now where can I find some of that happiness you speak of
09-28-2012 12:22 PM
panthermark ^What really sucks is that the TJ Rubi's actually had lockers WITH a mechanical LSD built in to the rear axle.

You had the best of both worlds.

My guess is that such a set-up was dumped on the JK's to save money. Software (BLD) is cheaper than hardware (mechanical LSD).
09-28-2012 12:12 PM
Rooster76 Here is a link that goes to the section on LSD from "Four-Wheeler's Bible" I wish I would have found it sooner and just posted this link.
LINK->Four-Wheeler's Bible - Jim Allen - Google Books

Quote:
Originally Posted by oilwell1415 View Post
Read the warranty book. The diff clutches are not listed under the what's not covered section, and the rear axle section of the powertrain warranty specifically says that all internal parts are covered. The last I checked the diff clutches were an internal part of the axle. They may balk at changing them, but their own warranty manual legally obligates them to change them.
Sorry, It does look like the clutch plates should be covered. Thanks SilverSport for clearing that up. If you can get them to replace the clutch pads that would be pretty sweet.

Quote:
Originally Posted by oilwell1415 View Post
How do I put this. You DON'T KNOW THE DIFFERENCE BETWEEN A TORSEN TYPE DIFF AND A CLUTCH TYPE DIFF and you are in here telling us how they work? Do about 30 seconds of googling and get yourself to a point that you can actually speak intelligently on the topic. One article you mentioned specifially said it had a Truetrac and the other specifically said a Torsen. Both of these are Torsen type GEAR diffs. They are not the clutch style like the OEM Trac-Lok unit. Good God man, you posted a video of the Truetrac (with a description that says it uses worm gears instead of clutches!) in post 6 and a picture of a clutch type in post 19. Did you not notice at all that the two work in a completely different way?
Bias Ratio is a term that covers all LSD systems. So to that regard it doesn't really matter what LSD system was featured.

The TJ article Off-Road Adventures Magazine (Post 26) was mostly about installing a truetrac. Below where the guy is yanking out out an axle, it compairs them to clutch based LSD's briefly.

In the first long winded post #6 I was trying to show that there are different types of LSD, and put them under different headings. Like the truetrac's that use worm gears instead of clutch plates.
WORM GEAR


Quote:
Originally Posted by oilwell1415 View Post
I don't care if you get the factory LSD or not. What irritates me is that people that don't have a clue how it works and have likely never even had one come into these threads and spout off about how bad it sucks and it's a waste of money. Then they proceed to tell the person asking the question that they should spend $1000 on a locker instead when their Jeep will rarely see dirt at all and will never be in a situation where it is more useful than the LSD for $240. Never mind that the LSD can work all the time while still being compelely streetable.
I agree with you there. Most people would be better served with an LSD over a locker. Especially if they don't know the difference, or how and when to use a locker. Much like, most people would be better served with an AWD Grand Cherokee over a part time 4WD wrangler in snow.

MISTAKES HAVE BEEN MADE
Quote:
DIFFERENTIAL OPTIONS - I will go through each in more detail below
  • Open Differential - What you get without the option or the only option for Rubicons (They will have BLD -Break Lock Differential explained below)
    LSD-Limited Slip Differential (on a JK it will work with the BLD) - Works good on road
  • Part-Time Lockers - Strictly off road use or if you get stuck
  • Full Time lockers - Strictly off road and more of a dedicated trail rig option.
I noticed that in post#6 that I said that open diff is the only option for Rubicons (that have part-time lockers). I meant it to say you could not add a factory Trac-Lok LSD option.

I also wish I would have just mentioned that lockers totally lock the axle when describing them. Hopefully the name is enough to imply that.
09-28-2012 12:04 PM
oilwell1415 Open means it is simply a regular differential. They call it that because there is an open hole in the middle of it where the guts of a limited slip or locker would be if it was one of those. It does nothing to force torque to the wheel with traction.
09-28-2012 12:00 PM
12JKUR This is gonna take me a bit to digest.

What is #25 on the exploded view of the diff above?

How does the term "open diff" come to play, what is "open"?
09-28-2012 08:57 AM
oilwell1415
Quote:
Originally Posted by Rooster76 View Post
I would doubt that the Trac-Lok clutch plates would be covered under warranty because they are a wear item. I know that manual transmission clutches and break pads are not. I'm sure you could ask a service guy while at the dealer and they would be able to tell you.
Read the warranty book. The diff clutches are not listed under the what's not covered section, and the rear axle section of the powertrain warranty specifically says that all internal parts are covered. The last I checked the diff clutches were an internal part of the axle. They may balk at changing them, but their own warranty manual legally obligates them to change them.

Quote:
How do I put this. Your Wrong. Don't take my word for it just do a search for Bias Ratio and you will see. Here is a quote below from a link I found that goes over Trac-Lok on TJ's.

also worth noting from that article

Here is another web site showing it transfers more torque over, hopefully to put it to bed. At least it will rest my case.
How do I put this. You DON'T KNOW THE DIFFERENCE BETWEEN A TORSEN TYPE DIFF AND A CLUTCH TYPE DIFF and you are in here telling us how they work? Do about 30 seconds of googling and get yourself to a point that you can actually speak intelligently on the topic. One article you mentioned specifially said it had a Truetrac and the other specifically said a Torsen. Both of these are Torsen type GEAR diffs. They are not the clutch style like the OEM Trac-Lok unit. Good God man, you posted a video of the Truetrac (with a description that says it uses worm gears instead of clutches!) in post 6 and a picture of a clutch type in post 19. Did you not notice at all that the two work in a completely different way?

Quote:
You seem to be really pissed off that I wouldn't get the factory LSD. It's not going to make your Jeep any worse. Maybe you have to add some special lube additive to the diff, but that's no big deal. In the end it is just my opinion. Like assholes everyone's got one and most of them stink.
I don't care if you get the factory LSD or not. What irritates me is that people that don't have a clue how it works and have likely never even had one come into these threads and spout off about how bad it sucks and it's a waste of money. Then they proceed to tell the person asking the question that they should spend $1000 on a locker instead when their Jeep will rarely see dirt at all and will never be in a situation where it is more useful than the LSD for $240. Never mind that the LSD can work all the time while still being compelely streetable.

The heading you used for post 26 should be your motto.
09-27-2012 11:06 PM
SilverSport I believe the "DSA" is just the option code Jeep uses for the Trac Loc LSD. Not aware of it meaning anything in regards to the LSD itself.

The 2012 Warranty Information book explains in Paragraph 2.1F the clutch discs are only covered under warranty for 12 months or 12K miles.

Paragraph 2.4E (Parts Covered) (Four-Wheel Drive (4X4): "axle housing and all internal parts. I read that to say the clutch packs would be covered under the 5 year/100K mile powertrain warranty.
09-27-2012 09:33 PM
Rooster76
"The wise man knows he doesn’t know. the fool doesn’t know he doesn’t know." ~Lao Tzu

Quote:
Originally Posted by oilwell1415 View Post
This. And don't forget that the "Rear axle housing and ALL internal parts" are covered under the 5yr/100k mile powertrain warranty, so you won't have to worry about it for a long time.
I would doubt that the Trac-Lok clutch plates would be covered under warranty because they are a wear item. I know that manual transmission clutches and break pads are not. I'm sure you could ask a service guy while at the dealer and they would be able to tell you.

Quote:
Originally Posted by oilwell1415 View Post
With a clutch type LSD there will never be more torque on the wheel with traction than there is on the one with no traction. All these types of diffs do is limit how readily the two axles slip compared to each other, hence limited slip.
How do I put this. Your Wrong. Don't take my word for it just do a search for Bias Ratio and you will see. Here is a quote below from a link I found that goes over Trac-Lok on TJ's.

Quote:
FROM Off-Road Adventures Magazine
How much limited slip action a particular diff will generate is built in. That effect can be measured and is expressed as the bias ratio. Bias ratio describes how much torque the limited slip can shuttle from the lower grip to the higher grip tire. The rear Truetrac used for our TJ has a bias ratio of around 3.5:1. That means for every 100 pounds-feet of grip the low traction tire can support, the Truetrac can deliver up to 350 lbs./ft. to the high traction tire. That low traction side figure will include the built-in braking force of the limited slip as well as whatever grip the tire can deliver (there's always a little grip, unless the tire is in the air). That 3.5:1 ratio remains constant.
also worth noting from that article
Quote:
They (clutch LSD) work well, though as the clutches wear, their performance tends to degrade.
Here is another web site showing it transfers more torque over, hopefully to put it to bed. At least it will rest my case.
Quote:
FROM HowStuffWorks "Locking and Torsen"
For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.
Quote:
Originally Posted by oilwell1415 View Post
If QTec gets $116 for them they are overcharging. You can get them a lot cheaper than that as shown by another poster already. They are covered by the powertrain warranty anyway, so it really doesn't matter what they cost.
It's possible. I also don't like how they make it harder to get free shipping anymore (no google checkout trick). Like I said It just popped up when trying to find a picture so I figured I would put what they charge for reference.

You seem to be really pissed off that I wouldn't get the factory LSD. It's not going to make your Jeep any worse. Maybe you have to add some special lube additive to the diff, but that's no big deal. In the end it is just my opinion. Like assholes everyone's got one and most of them stink.
09-27-2012 08:12 PM
oilwell1415
Quote:
Originally Posted by panthermark View Post
I think he is trying to figure out if he wants to order LSD or not.....and how much possible replacement packs cost down the road.
The first two or three should be covered under warranty.
09-27-2012 08:12 PM
oilwell1415
Quote:
Originally Posted by Rooster76 View Post
I've done my reply in a goofy fashion that prevents it from being quoted and easily responded to, so everyone now gets to suffer through bouncing back and forth to see what was previously said.
With a clutch type LSD there will never be more torque on the wheel with traction than there is on the one with no traction. All these types of diffs do is limit how readily the two axles slip compared to each other, hence limited slip.

If QTec gets $116 for them they are overcharging. You can get them a lot cheaper than that as shown by another poster already. They are covered by the powertrain warranty anyway, so it really doesn't matter what they cost.

You are correct that the BLD only applies the brake to one wheel. If you look at the mechanics of how a differential works you can easily see that if one wheel is locked only half of the torque goes to the other wheel because of the way the spider gears interact. With one wheel locked all of the power goes to the other side, but the tire spins twice as fast at half the torque.
09-27-2012 07:58 PM
Frogy I had a trac lock on my 93 wrangler and liked driving my jeep over my brothers with an open diff on roads, but the trac lock was not very effective off road, my tl blew up ( carrier cracked) at about 170 k and I went to a Detroit, which is really not for the faint of heart. If I had to choose my ideal I like the idea of ected's but have heard they're crap. My answer to the original question would be get the tl if you don't plan on a real locker soon, you will enjoy the tl over an open diff
09-27-2012 07:47 PM
panthermark
Quote:
Originally Posted by SilverSport View Post
Are you trying to put Trac Loc in an open diff? The carriers are different.
I think he is trying to figure out if he wants to order LSD or not.....and how much possible replacement packs cost down the road.
09-27-2012 07:44 PM
SilverSport Are you trying to put Trac Loc in an open diff? The carriers are different.
09-27-2012 07:38 PM
panthermark I know there are a couple of packs available....but I'm trying to see if these are the correct ones.

Standard D44 - $66.61 + $8.02 shipping
Dana 44 & 9.25 Chrysler TracLoc clutch kit. : Amazon.com : Automotive

Aggressive Pack D44 - $129.49 + $8.02 shipping
Dana 44 Power Lok clutch kit,aggressive posi. : Amazon.com : Automotive
09-27-2012 06:46 PM
Rooster76
You use steel to sharpen steel, and one friend sharpens another.

BLD=ELSD(electronic limited slip differential - another term used in the Chrysler blog link above)=Part of the traction control system
I found a way better video showing BLD in action
2008 JEEP JK Brake Lock Differential(BLD) - YouTube
I found BLD mentioned in the 2012 manual on page 419 under traction control. It doesn't mention anything about only working in 4WD like the video implies.

2012 Owner Manual
Quote:
Traction Control System (TCS)
This system monitors the amount of wheel spin of each of
the driven wheels. If wheel spin is detected, brake
pressure is applied to the slipping wheel(s) to provide
enhanced acceleration and stability. A feature of the TCS
system functions similar to a limited slip differential and controls the wheel spin across a driven axle. If one wheel
on a driven axle is spinning faster than the other, the
system will apply the brake of the spinning wheel. This
will allow more engine torque to be applied to the wheel
that is not spinning. This feature remains active even if
TCS and ESC are in either the “Partial Off” or “Full Off”
modes. Refer to “Electronic Stability Control (ESC)” in
this section for further information.
Here is what the owner manual says about Trac-Lok. Guess that clears up the right spelling. Figured I would add it because I had the owner manual open.

2012 Owner Manual
Quote:
TRAC-LOK REAR AXLE — IF EQUIPPED
The Trac-Lok rear axle provides a constant driving force
to both rear wheels and reduces wheel spin caused by the
loss of traction at one driving wheel. If traction differs
between the two rear wheels, the differential automatically
proportions the usable torque by providing more
torque to the wheel that has traction.
Trac-Lok is especially helpful during slippery driving
conditions.With both rear wheels on a slippery surface, a
slight application of the accelerator will supply maximum
traction.
Quote:
Originally Posted by oilwell1415 View Post
It always amazes me that the people who have no idea how a clutch type LSD works are the ones talking about how horrible they are. They don't sense anything and they doesn't respond by sending power to the other wheel. They are ALWAYS sending power to both wheels. They allow the wheels to slip during a turn. The more torque you put in the harder they lock both wheels together. It is true that they never fully lock and that the clutches wear out over time. The former isn't that big of a deal unless you are a hardcore wheeler and the latter can be easily fixed every few years with a $70 set of clutches and an hour of your time.

With LSD more torque will get transferred over from the tire will less traction (slipping) to the tire with more traction. It is expressed as "Bias Ratio" (most common) or a "locking factor" %. These terms exist because it is a phenomenon. (there is more about that in my quote from above)

Trying to find a good picture I found Trac-Lok replacement clutch plates on Quadratec for $116. They are show in #10 from->Jeep® Wrangler JK Axle & Differential Parts - Quadratec


The owner's manual says that BLD works all the time, but it is not a replacement for a LSD for several reasons. First, it is a reactive system. A wheel has to slip for a few seconds before it takes action. An LSD works to prevent the wheel from slipping in the first place.

I agree Trac-Lok LSD is always at work trying to hold the plates together. The clutch plates are preloaded with tension. They act like a break being applied to hold both sides rotating at the same speed. For that reason they will pick up faster. I would tend to think it would be smoother because it is exerting more of a constant pressure. The BLD that sort of looks jerky from the video when it kicks in.

Second, when the BLD is working it reduces the torque available at the tire with traction by half.

I'm pretty sure that only the spinning tire gets the break applied. I don't think it puts the breaks on both wheels on the axle that would reduce some torque.

An LSD supplies full torque to both wheels until the difference in torque between them becomes so great that the clutches slip.
09-27-2012 05:21 PM
mcgee10 BLD is not taking you very far off road. Better try it out a few times first and have a friend with you that has a strap or a winch. My first trip out I knew it wasn't going to work for me. For some mild off road your BLD may work.
09-27-2012 04:40 PM
MTH
Quote:
Originally Posted by NWranglerS View Post
Can someone briefly explain the difference between the traction control that comes stock and the upgradable Limited slip diff?
See Rooster's detailed post above. He has a separate section each for the BLD system (the "traction control") and the upgraded LSD.

In short, the BLD system uses the brakes to reactively simulate an LSD. An LSD sits in the center of your axle housing a proactively does its job.
09-27-2012 04:26 PM
NWranglerS Can someone briefly explain the difference between the traction control that comes stock and the upgradable Limited slip diff?
09-27-2012 02:17 PM
oilwell1415
Quote:
Originally Posted by panthermark View Post
1. IMO, yes...but that also depends on where you live. If you live in....Dallas...and every road around you is paved and dry.....you might not need it is much. But if you live someplace where you have to deal with slick, wet roads, or lots of gravel...you should get it.

2. It is located inside of the the pumpkin on your rear axle and is always "on"....so it helps with both.

3. Yes, every 40,000-50,000 miles (depending on wear). But keep in mind that if you never replace the clutch packs, it will eventually perform like an open differential anyway.

LSD is a must have deal breaker for me. I know there are better units available, but not installed for $295 MSRP.

If you are going to do hard-core off-roading....save your money and get something different. But if you will be a mall crawler (as I will be), and you have to deal with slick roads, and patchy ice in the winter......get it.
This. And don't forget that the "Rear axle housing and ALL internal parts" are covered under the 5yr/100k mile powertrain warranty, so you won't have to worry about it for a long time.
09-27-2012 01:59 PM
panthermark
Quote:
Originally Posted by BenDiem View Post
Wow, great info...

Thanks for the informative posts Gents; I just have a couple more questions relating to the OP's post...

Still slightly confused:

1. For a mall crawler, is DSA worth the small increase in price ($295)?
2. Does DSA provide a benefit in 2WD or 4WD mode, or both? The answer to this question will be the deciding factor.
3. Is DSA a maintenance issue for mall crawlers in the future?

Tks/B
1. IMO, yes...but that also depends on where you live. If you live in....Dallas...and every road around you is paved and dry.....you might not need it is much. But if you live someplace where you have to deal with slick, wet roads, or lots of gravel...you should get it.

2. It is located inside of the the pumpkin on your rear axle and is always "on"....so it helps with both.

3. Yes, every 40,000-50,000 miles (depending on wear). But keep in mind that if you never replace the clutch packs, it will eventually perform like an open differential anyway.

LSD is a must have deal breaker for me. I know there are better units available, but not installed for $295 MSRP.

If you are going to do hard-core off-roading....save your money and get something different. But if you will be a mall crawler (as I will be), and you have to deal with slick roads, and patchy ice in the winter......get it.
09-27-2012 01:49 PM
BenDiem Wow, great info...

Thanks for the informative posts Gents; I just have a couple more questions relating to the OP's post...

Still slightly confused:

1. For a mall crawler, is DSA worth the small increase in price ($295)?
2. Does DSA provide a benefit in 2WD or 4WD mode, or both? The answer to this question will be the deciding factor.
3. Is DSA a maintenance issue for mall crawlers in the future?

Tks/B
09-27-2012 09:36 AM
oilwell1415 It always amazes me that the people who have no idea how a clutch type LSD works are the ones talking about how horrible they are. They don't sense anything and they doesn't respond by sending power to the other wheel. They are ALWAYS sending power to both wheels. They allow the wheels to slip during a turn. The more torque you put in the harder they lock both wheels together. It is true that they never fully lock and that the clutches wear out over time. The former isn't that big of a deal unless you are a hardcore wheeler and the latter can be easily fixed every few years with a $70 set of clutches and an hour of your time.

The owner's manual says that BLD works all the time, but it is not a replacement for a LSD for several reasons. First, it is a reactive system. A wheel has to slip for a few seconds before it takes action. An LSD works to prevent the wheel from slipping in the first place. Second, when the BLD is working it reduces the torque available at the tire with traction by half. An LSD supplies full torque to both wheels until the difference in torque between them becomes so great that the clutches slip.
09-26-2012 10:11 PM
Rooster76 I'm sort of curious what does DSA (as in the title of the post) stand for. It seems that Jeep's marketing department is way too creative in coming up with new names, for things with names .

Quote:
Originally Posted by MeadHawk View Post
The way I understand it is the Auto LSD would mostly be beneficial when in 2 wheel rear wheel drive when BLD is not in operation. BLD is functional only in 4 wheel low and high which will pretty much make the LSD useless as the BLD will be doing the same thing but using yours brakes to do it.
BLD WORKS IN 2WD ... Right?
Looks like that command trac video just muddied the water. I think BLD works in 2WD. The official Jeep command trac video (couple post above) makes it seem like it is a 4WD only option. I have found a few post that echo that it works in 2WD, but nothing that absolutely put's it to bed.

BLD will enhance LSD giving the axle a higher locking factor. They both are trying to lock the axle and do it in different ways by putting more friction(resistance) on the spinning tire=more toque=more ablity to push and not just spin. They don't counter act each other, or replace each other. I'm very certain that this is the case.
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