Quadra-Drive VS. Quadra-Trac [Archive] - Jeep Commander Forums: Jeep Commander Forum

: Quadra-Drive VS. Quadra-Trac


shmily524
03-05-2007, 09:59 AM
Could anyone explain the difference between the two, besides that fact that QD has locking diffs?

I got my Commander for $22K new with the 4.7l, tow package, etc as an '06 leftover. To get the Quadra-drive, I would have had to pay for an '07 (15K more), and I felt this was too good of a deal to pass up.

Basically, my question is what specific disadvantage does the QT have to QD?

Thanks!

rubicontrail.net
03-05-2007, 10:13 AM
Quadra-Trac I: Has No Low Range
Quadra-Trac II: Has Low Range
Quadra-Drive II: Has Low Range, Electronic Limited Slip Differentials

Quadra-Drive II can shift all available torque to the wheel(s) that have traction within milliseconds. Whether you need it or not depends on what you plan to do with your Commander and how much snow and ice you deal with. What's important is that you got a 4WD Jeep. Those that say they don't need it because they don't go off-roading, don't have snow, etc., don't realize that the 4WD Commander will handle much better on rain slicked roads than the 2WD Commander.

shmily524
03-05-2007, 10:37 AM
Awesome!
I think I would rather have the QD, but it was not worth that many thousands of dollars. We routinely spend a lot of time in the snow (Colorado), but I will not be doing any seriour off-roading in this rig until it is 4-5 years old. Thinking I could add locking diffs then if I need them...

I think the on-board traction control system will suffice for the time in the snow/rain for now...

Thanks for the info!

commanderlimited
03-06-2007, 09:53 PM
do any of the 06 commanders have the qd. My window sticker says that I have front and rear limited slip locking diff's.

rwmorrisonjr
03-06-2007, 10:25 PM
All Limiteds are equipped with QDII.

jeep5253
03-06-2007, 11:15 PM
All Limiteds are equipped with QDII.
Sorry, but that is not correct. Quadra-Drive II only comes standard with the 5.7L HEMI. It is an option with the 4.7L.

jeep5253
03-06-2007, 11:40 PM
Basically, my question is what specific disadvantage does the QT have to QD?

Quadra-Drive II can send 100% of the engine torque to any tire (or tires) that has traction. For example, if both left side tires are slipping then all of the power would be sent to both of the right side tires; if three tires are slipping all of the power would be sent to the one tire that has traction. With the Quadra-Trac the power is sent either to the front axel or the rear axel but cannot be sent to specific tires.


Could anyone explain the difference between the two, besides that fact that QD has locking diffs?


Quadra-Drive II does not have locking differentials--it has front and rear electronic limited slip differentials.

commanderdrone
03-07-2007, 08:27 AM
do any of the 06 commanders have the qd. My window sticker says that I have front and rear limited slip locking diff's.

Yes, QDII is available on 06 commanders. You can tell if you have it by looking between your shifter and your cup holders. If it says "Quadra-Drive II", then you've got it =)

!c

another chris
03-07-2007, 12:29 PM
Quadra-Drive II can send 100% of the engine torque to any tire (or tires) that has traction. For example, if both left side tires are slipping then all of the power would be sent to both of the right side tires; if three tires are slipping all of the power would be sent to the one tire that has traction. With the Quadra-Trac the power is sent either to the front axel or the rear axel but cannot be sent to specific tires.


Quadra-Drive II does not have locking differentials--it has front and rear electronic limited slip differentials.


You're 95% right; I'm sure you just miss worded a statement so I'll clarify that if the three tires, you mentioned above, where to have slippage, electronically it's sensed and the clutch basket/plates will engage a thrust/side pin of some sort distributing power from the ONE tire that HAS traction to the 3 that DON'T.

Overall, the limited slip is a plus for tires that do not leave the ground. If you were to have a tire or two...or three to leave the ground, limited slip is pretty much useless. This is where a locker would be effective unless you know how to work the e-brake w/ the e-slip to create a some what "posi-traction" OR rock the vehicle so the spinning wheels can grab because whichever tire is on the ground...most likely it will nothing more but a kickstand.

Also, it depends on how much you off-road and what you do w/ your vehicle. If you want those tires that are up off the terrain from an off-camber/hung up wheeling scenario to get traction, lockers dominate. That's a whole different chapter though.

jeep5253
03-07-2007, 02:27 PM
You're 95% right; I'm sure you just miss worded a statement so I'll clarify that if the three tires, you mentioned above, where to have slippage, electronically it's sensed and the clutch basket/plates will engage a thrust/side pin of some sort distributing power from the ONE tire that HAS traction to the 3 that DON'T.

another chris, No I am not wrong on this. I have owned a 2000 GC with Quadra-Drive for seven years and thoroughly understand how it works. Anyway, why would you want to send power to the tires that do not have traction? You want it to go to the one with traction to pull you out. If you don't believe me go to the Jeep website and check it out: http://www.jeep.com/4x4/index.html?dvar=5 put you cursor on "GET READY" and then click on "See How Jeep 4x4 Systems Work". Apology accepted.

John
03-07-2007, 02:47 PM
As a long time serious offroader with now 4 jeeps, all with different 4wd combinations and the TJ locked front and rear I cast my vote with the final poster 5253.

Bulldog9
03-07-2007, 05:03 PM
OK boys, put away your rulers........... :D

rubicontrail.net
03-07-2007, 08:35 PM
John and Jeep5253 are correct. Lockers are ideal for off-roading/rock-crawling but the Quadra-Drive II system is the best overall traction system. Off-road a locker system will win but on a slippery road the ELSDs win because they can actually be used at speed without damage to the drive train.

another chris
03-09-2007, 04:55 PM
another chris, No I am not wrong on this. I have owned a 2000 GC with Quadra-Drive for seven years and thoroughly understand how it works. Anyway, why would you want to send power to the tires that do not have traction? You want it to go to the one with traction to pull you out. If you don't believe me go to the Jeep website and check it out: http://www.jeep.com/4x4/index.html?dvar=5 put you cursor on "GET READY" and then click on "See How Jeep 4x4 Systems Work". Apology accepted.

Whooaa…easy there big fella.

I do apologize, for some reason I was thinking ass-backwards. Trying to read, think and respond here @ work might have played part in that. I feel like a dum-dum now since this was the first time I read back on that post..haha. Having more power applied to the slipping tires would be pointless. I've owned numerous 4wd's w/ different systems and only two Rams I've had were LSD's so I'm pretty familiar w/ it all as well….read the TJ's sig below which was pretty much built and not bought ;)

However, you're 100% right on the QD-II but still 95% right w/ a typical Limited slip because the power distributes @ a roughly 50/50 trying to even itself out. I was thinking the typical and not QD-II's system which is what probably threw me off and responded that the power is sent to the non-traction tires. That would make it pointless all-together to have 4wd.

I'm going to start triple checking my responses before submitting them from here on out…sheesh!

//EDIT// I still stand w/ my Posi comment though. Use your e-brake to try and trick the LSD sensors.

dieselenthusiast
06-05-2010, 09:28 PM
subscribing to learn

Swanny
06-05-2010, 11:26 PM
subscribing to learn

What are you expecting to learn from a thread where the post previous to yours is over three years old? :icon_confused:

powerslave1966
06-05-2010, 11:41 PM
What are you expecting to learn from a thread where the post previous to yours is over three years old? :icon_confused:

Well, not all of us are 4x4 Guru's or experts on the Commander itself, this thread however old it is will probably help the next newbie now or in the future so thanks for keeping it alive!!!:orangehat:

SAL-XK
06-06-2010, 12:07 AM
Doesn't the QT2 use the traction control system to trick the limited slip axle in sending the power to the wheel with traction. A normal limited slip the tire with out traction will spin all day use to have to pump the breaks to try an trick it to send power the other way. I know QD2 uses clutches and stuff to do this electronically and can temporarily mimic a locker.

robby
06-06-2010, 06:50 AM
Sal,
The traction control mimics a limited slip by applying brake pressure to the spinning wheels brakes, forcing power to the non- slipping wheel.
The QTII systems use open differentials, there are no clutches involved.

The QDII is the only version that has limited slip units and they are electronically engaged.
When in 4HI, the QD system differentials operate as open units, with no limited slip available.

Rob

SAL-XK
06-06-2010, 09:22 AM
Sal,
The traction control mimics a limited slip by applying brake pressure to the spinning wheels brakes, forcing power to the non- slipping wheel.
The QTII systems use open differentials, there are no clutches involved.

The QDII is the only version that has limited slip units and they are electronically engaged.
When in 4HI, the QD system differentials operate as open units, with no limited slip available.

Rob

Rob, I just want to understand this system completely. You say open differentials isn't that limited slip like found on a suburban or a any rear wheel car. Do the wheels spin at different speeds when taking turns on the street. And with out the traction control the slipping wheel would spin all day and I would be stuck like with a suburban. So I have this correct the QT2 uses the brakes to trick the axle in supplying the tire with grip. The QD2 uses clutches to electronically put power to the wheel with traction in a lot less time. Doesn't the QD2 also have a small pump or something when access wheel spin is happening it locks the wheels together like a locker for brief moment or two. Now that being said does that not make QT2 the best system for upgrading to lockers.????

robby
06-06-2010, 10:19 AM
Lets see here.....
I'll reiterate a bit....The open differental regardless of manufacturer has nothing internally to prevent the axles from spinning independently of one another.
So, forgetting the front differental for the moment, if we lift one rear wheel of a QTII system, off the ground, and the traction control was disabled, start the engine and put it in gear, the raised wheel will spin, the wheel on the ground will do nothing.
There are no clutches, no link if you will, between the left and right axle, beyond the spider gears.
Now, if we introduce traction control, which is nothing more than electronic brake application, to the spinning wheel, power, that needs to go somewhere, will be redirected to the other axle through the spider gears.
As a result, the wheel with traction is forced, to turn.
There is a vidieo somewhere demonstrating this.
You can see the unloaded wheel lock/unlock/lock about at the speed you read that.
The benifit of this system is less moving parts at the expense of potentaly increased brake wear and not quite as smooth as a true limited slip.

A limited slip differental as provided by most manufacturers, are catagorized as two types: Clutch type and Differing speed sensative.
The clutch type has a clutch stack (several friction and steel plates stacked, some other designs use cone shaped clutches) on either side of the spider gears that the axles slide into.
The tightly compressed clutches resist any slipping untill their mechanical limits are exceeded, at which point a controlled slip occurs.
Because of the resistance the clutches provide, power will be distributed to both axles through the spider gears.....but remember, I said till the clutch limitation is exceeded.
That is why you can turn without the rear tires chattering as they rotate at different speeds till the vehicle is straight again.
So, this is a limited slip design.
Some of us old guys will remember applying the parking brake in a controlled manner to force a limited slip type reaction on a open rear end....useful in snow.
The differing speed type (found in my old Blazer) is actually a flyweight controlled locker.
When one axle speed is 20% greater than the other, the flyweights are thrown out into a mechanism that locks the axles together....works well but abuse = scattering of little parts and the attendent gear munching that follows.

Jeep is the only manufacturer using a electically locking CLUTCH system.
I capitalized clutch because there are electronic lockers out there with no clutch, such as Toyota.
The Jeep system will slip when engaged, but just before a axle breaks.
Those who tried a QDII system on dry ground have heard the attendent banging/cracking noise that occurs just as the QDII clutches slip.
IMO one of the most well thought out systems available.
In addition, the QDII has the same traction control system as a side benifit.

As a side note, the Toyota system, locked on dry ground, will break things and the owners manual forewarns the operators that this is abuse and not covered under warranty.

I may have left some points out, but I tried to keep it understandable.

Rob

SAL-XK
06-06-2010, 10:30 AM
Cool thanks for the explanation I was close in my understanding of the system. Now I think I understand the system a lot better with more clarity. Any thoughts or is it even possible to install lockers in either system.

robby
06-06-2010, 10:39 AM
Cool thanks for the explanation I was close in my understanding of the system. Now I think I understand the system a lot better with more clarity. Any thoughts or is it even possible to install lockers in either system.

Several members have looked into the possibility of lockers but I don't believe there is anything available.

Rob

SAL-XK
06-06-2010, 11:53 AM
This is a link that visually shows how the open and limited slip works
http://www.youtube.com/watch?v=q-rQTHMVAuw

robby
06-06-2010, 03:39 PM
The G-80 is the design I mention installed in my Blazer.
The examples of the limited slip on the rollers is an example of the clutches behaviour when their limits are exceeded.

Somewhere.....and you can bet 5253 knows were, there is a similar video of QDII doing its thing.

The advantage of the GM G-80 (Eaton) is that it will operate in either transfer case range.
Like I said earlier though....not the strongest design I've been around.
Naturally, repairmen will tend to give something a bad rap.....we only see the broken ones and forget about the millions of them that have no problem for their entire service life.
My Blazer has never had a locker problem....several carrier bearings/pinion bearings, but it has a excuse.....247k today.

Rob

SAL-XK
06-06-2010, 03:58 PM
I actually found the commander listed in the ARB vehicle application list. It might be possible to get air lockers for the commander.

dieselenthusiast
06-06-2010, 04:23 PM
I actually found the commander listed in the ARB vehicle application list. It might be possible to get air lockers for the commander.

Are you sure? The ARB USA website I looked at did not include the Commander........

SAL-XK
06-06-2010, 04:55 PM
Are you sure? The ARB USA website I looked at did not include the Commander........

Yes sir the web page said ARBUSA.COM then hit air lockers then applications and it takes me to arb.com.au and listed the commander. I think au is Australia but makes sense to me there list would be stored in a AU server. I have several ARB dealers near me I was planing on calling one up and having them figure it all out. and all the vehicals are american in the list so I assumed it was correct. Even if it was for international the axles are the same I would think.
http://arb.com.au/resources/pdf/airLockers/application_chart.pdf

dieselenthusiast
06-06-2010, 09:05 PM
Yes sir the web page said ARBUSA.COM then hit air lockers then applications and it takes me to arb.com.au and listed the commander. I think au is Australia but makes sense to me there list would be stored in a AU server. I have several ARB dealers near me I was planing on calling one up and having them figure it all out. and all the vehicals are american in the list so I assumed it was correct. Even if it was for international the axles are the same I would think.
http://arb.com.au/resources/pdf/airLockers/application_chart.pdf

Don’t get your hopes up. Like I said, ARB does not list their lockers for the US application for a reason. Lets hope that the information is wrong, but I’ve seen this happen before.

cico7
06-08-2010, 11:07 AM
Following Sals request, I looked up more info on Lockers.
Locking Differential

Provides even more traction than a limited-slip differential by “locking” the axle shafts together when the driver wants to do it. Locking differentials do not allow for wheel-speed differences and must not be used on dry, paved roads.

Open-Center Differential
Located in the transfer case on some full-time four-wheel-drive vehicles, this component works in the same way as an open differential in the axles, but is of a more compact design. This component employs a planetary gearset, with planetary gears that revolve around the sun gear and inside the ring gear.


Gives me a better idea of what's going on...

GPintheMitten
06-08-2010, 02:41 PM
Here's a video of Jeeps 4x4 system. It's a long one, so fast forward to the 5 minute mark to see the Commander's performance. This one is the QDII system with Electronic Limited Slip (electronically locks). Enjoy.

In the Commander obstacle at about the 6:55 minute mark, you can't see but it is climbing on rollers to simulate low/no traction on some wheels. More evident if you watch the Liberty in action in the beginning of the video.

http://www.youtube.com/watch?v=Im7_MKP4HtA&feature=related

cico7
06-08-2010, 07:00 PM
12:14 mentions the air actuated lock, true locking system on the wrangler..

Yeggster
06-09-2010, 06:14 PM
Sal,
When in 4HI, the QD system differentials operate as open units, with no limited slip available.

Rob

This is not true the Eaton lockers are always active ithey are wired into the traction control and roll over mitigation system etc.

07JeepXK
06-09-2010, 07:27 PM
I just went on jeep.com and watched the video on how jeep 4x4 systems work for quadra drive II and it looks to me like the limited slips work in 4 HI.

robby
06-09-2010, 09:12 PM
Oh well,
I am, once again, somewhat confused.....maybe.
I really wasn't taking the traction control into consideration because the open diff also uses it when in 4hi on our Commanders.
I was comparing it to a conventional limited slip or a G80 type locking system, meaning, the clutchs aren't activated in 4 hi and gave no consideration to traction control systems.
My focus was just what is happening within the differential.

Rob

07JeepXK
06-09-2010, 10:19 PM
Who knows, really no sense arguing. In the end QD II is awsome regardless of how it works/operates. :bowdown:

Yeggster
06-09-2010, 10:23 PM
Oh well,
I am, once again, somewhat confused.....maybe.
I really wasn't taking the traction control into consideration because the open diff also uses it when in 4hi on our Commanders.
I was comparing it to a conventional limited slip or a G80 type locking system, meaning, the clutchs aren't activated in 4 hi and gave no consideration to traction control systems.
My focus was just what is happening within the differential.

Rob

The clutches are definitely used with traction control .. the breaking system is used in combination the Eaton Differential Clutches not in juxtaposition.

dieselenthusiast
06-09-2010, 10:30 PM
Who knows, really no sense arguing. In the end QD II is awsome regardless of how it works/operates. :bowdown:


I agree………….. It’s perfect for what most of us will ever need the Jeep for. Although I must confess, I’ll be installing front and rear ARB lockers in the Jeep Liberty when I regear to 4:10’s.

Yeggster
06-09-2010, 10:41 PM
I agree………….. Jeep Liberty

How do you like the Liberty ... my wife is gong to be getting a new car this fall possibly and was thinking of a used one.

GPintheMitten
06-09-2010, 10:49 PM
My wife had 2 different model year Liberty's. She loved them. I could not get comfortable in them. I haven't been in the new redesigned Libertys.

Yeggster
06-09-2010, 10:52 PM
My wife had 2 different model year Liberty's. She loved them. I could not get comfortable in them. I haven't been in the new redesigned Libertys.

Thanks for the input .. sounds like it might be good for her then

dieselenthusiast
06-09-2010, 11:13 PM
How do you like the Liberty ... my wife is gong to be getting a new car this fall possibly and was thinking of a used one.

I really like the Jeep Liberty. I highly recommend the Selec-Trac, NP242 transfer case for those who use it for a daily driver. The 3.7L is a little underpowered IMO, but overall I’m happy with it. I traded my 2005 2.8 VM Motori Diesel for a 2007 gasser, which I regret. The IFS suspension rides very nice. I have the OME coils and it rides better than stock. I have the 42RLE trany which seems to hold up very well. I know several people who are near 200,000 miles without any issues. 2006 and 2007 have window regulator issues, but Mopar seem to have finally fixed it. I like it enough that I will never sell or trade it.