DSA Anti-Spin Differential Rear Axle - Page 2 - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > JK Jeep Wrangler Forum > JK General Discussion Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 09-28-2012, 11:12 AM   #31
Jeeper
 
Rooster76's Avatar
 
Join Date: Oct 2011
Location: Indy
Posts: 817
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.

__________________
2012 JKR 2DR 6-Speed
Rooster76 is offline   Quote Quick Reply
Old 09-28-2012, 11:22 AM   #32
rotaredoM

WF Supporting Member
::WF Moderator::
 
panthermark's Avatar
 
Join Date: Aug 2011
Location: Chicago-land
Posts: 9,749
Images: 13
^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).

panthermark is offline   Quote Quick Reply
Old 09-28-2012, 12:07 PM   #33
Jeeper
 
Join Date: Jan 2012
Location: D/FW
Posts: 333
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
__________________
2012 JKUR (doh)
Auto, Freedom, 410's, in Black
12JKUR is offline   Quote Quick Reply
Old 09-28-2012, 12:17 PM   #34
Supporting Member

WF Supporting Member
 
SilverSport's Avatar
 
Join Date: May 2011
Posts: 21,299
Send a message via Yahoo to 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.
__________________
"Own a Jeep and own a piece of history."

"The Hunter is not concerned with the opinion of the Wolf."
SilverSport is offline   Quote Quick Reply
Old 09-28-2012, 01:55 PM   #35
Jeeper
 
Join Date: Jul 2011
Location: Broken Arrow, OK
Posts: 2,305
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.
__________________
2012 Silver Sport S, Silver, 6 speed, soft top, 3.73s, LSD, PCG, Infiniti, deep tint windows, Pro Comp 1028 wheels, 33" Duratracs, Smittybilt bumpers and steps, KC fog lights, Mopar slush mats and fuel door.

Happiness is a belt fed weapon.
oilwell1415 is offline   Quote Quick Reply
Old 09-28-2012, 03:38 PM   #36
Jeeper
 
Rooster76's Avatar
 
Join Date: Oct 2011
Location: Indy
Posts: 817
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.
__________________
2012 JKR 2DR 6-Speed
Rooster76 is offline   Quote Quick Reply
Old 09-28-2012, 04:10 PM   #37
rotaredoM

WF Supporting Member
::WF Moderator::
 
panthermark's Avatar
 
Join Date: Aug 2011
Location: Chicago-land
Posts: 9,749
Images: 13
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.
panthermark is offline   Quote Quick Reply
Old 09-28-2012, 04:40 PM   #38
Jeeper
 
Join Date: Oct 2009
Location: 513
Posts: 78
^^^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
BenDiem is offline   Quote Quick Reply
Old 10-17-2012, 10:49 AM   #39
Newb
 
Join Date: Sep 2012
Posts: 6
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!
floodwaker is offline   Quote Quick Reply
Old 11-28-2012, 01:55 PM   #40
Jeeper
 
rich67's Avatar
 
Join Date: Nov 2012
Location: Tampa
Posts: 195
Great thread indeed. Glad I got the option now.

__________________
2013 Wrangler Unlimited
Commando Green
rich67 is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




» Featured Product

All times are GMT -5. The time now is 06:32 AM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC