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Quadra Drive II vs. Quadra Trac II

140K views 56 replies 32 participants last post by  w4Rd3n 
#1 ·
Did you guys realize that most of you are probably buying a Limited or Overland and they come standard with the Quadra Trac II and not the top of the line Quadra Drive II. Correct me if I am wrong, but it used to be when your ordered a WK Limited or Overland you not only got the skid plates standard, but also the Quadra Drive II which is a superior 4-wheel drive system.
 
#3 · (Edited)
Re: Quadra Drive II vs. Qudra TracII

For the USA:

I don't believe skid plates are standard on any WK2, only available in an ORA package.

QD has never been available, let alone standard, on a V6 WK2.

In 2011, QD was standard only on the V8 Overland and Summit, not the Limited. The QD option was restricted on other models most of the year, however. In 2012 only the Summit V8 has QD standard. QD is in the ORA II package for V8s, however, and not as much restricted.

QD is better, dunno about how superior now that they don't put ELSD in the front diff.
 
#8 ·
Re: Quadra Drive II vs. Qudra TracII

Maybe I don't understand the how both QDII and QTII works but something about the audio explanation between the two systems on the link above doesn't make sense.

The guy explains in the QDII system says that when 'traction is lost' in any of the wheels that the QDII instantly transfers all of the torque to the wheels with the most traction.

However in the QTII system audio he says that QTII instantly transfers torque to the 'slipping axle' which implies to me that the wheels with the least amount of traction are getting the boost in torque.

Is the audio incorrectly describing what should be happening in QTII? It makes no sense to me to transfer torque to an axle that is spinning. :confused:
 
#9 ·
It appears the audio is not correct

"QTII instantly transfers torque to the 'slipping axle' "

Both QT II and QD II use the same transfer case which has a limited slip diff internally, so if your from wheels (i.e. front axle) do not have traction, the case can send nearly all the torque to the rear axle. The system uses brake traction control between the wheels on the same axle to minimize the spin of a wheel without traction and getting more torque to the wheel that has it.

QD II adds a limited slip diff to the rear axle, so instead of using brake traction in the rear, the diff does the work.

The front diff is open regardless.
 
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#11 ·
That's why I ordered mine with the adventure off road pack as part of that pack is the inclusion of the quadra drive II system
 
#15 · (Edited)
Gives you more power for tight spots, and spins the wheels much less. If you never run into situations where QD is a benefit, the QDII and QTII fitted into the WK2 work the same (they use the same transfer case).

QD adds a limited slip/locking differential to the rear end to limit spin instead of the relatively inefficient brake traction control. Brake traction control requires wheel spin to work, where the differential spin control usually does not. The end result is much less wheel spin, which is nice on snow or a gravel covered hill climb, and a bit more HP available to power through a rough spot or up a hill.

So, given the same driver skill and otherwise identical trucks, there may be severe situations where a QTII Jeep will be bogged down or stuck, but the QD Jeep will not. There will be plenty of situations, like shown in the video, where there is a bunch of QTII tire spin and pauses but the QD will just motor through smoothly.

The QD system has changed over the years more than brake traction control, the electric models in the current WK2 is more responsive than the older hydraulically actuated. Just saying that you need to consider those changes when discussing how well QD performed in the past.
 
#17 ·
Impressive demonstration. The video really shows the differences between QTII and QDII. I wonder why QDII is only available with the larger engine? Does limited slip require more horsepower to perform?
 
#19 ·
Just marketing, wasn't always like that. Perhaps Jeep marketing found that there was so little demand for a V6 QD that it was not worth the effort. There is not that much demand for the QD to begin with, kinda expensive and requires special dif oil and more routine maintenance. Their studies probably show that folks that want uncompromised traction also want uncompromised power.... or that QD guys will pay top dollar, so force them to also spent the money on the more profitable V8...

Its just marketing...
 
#20 ·
When we asked awhile ago, Jeep engineering said the WK2 traction computer is so much more processing power (quicker response) and with updated algorithms that front ELSD is of insignificant benefit, not worth its disadvantages. You may notice the QT WK2 spinning tires a little less than than the QT WK in that video. So you would expect the front tire of the QD WK2 to continue to rotate while its off the ground, but there would be little or no wheel spin for those tires on the ground. The WK2 QD should handle that situation a little less dramatically than the WK QD. But as the video says, all the systems got the Jeep though that obstacle. I think for aggressive rock crawling you'd want lockers front and rear, but then you are in a Wrangler anyway.
 
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#21 ·
I thought ELSD and "electronic locking diff" are a marketing way of saying "open diff with brake assist".

I have seen this in street cars and on a track, for example, those using brakes to turn and power out will be using their rear brake pads down faster.

I too can't really get a good answer to how the QDII is different than the open rear diff when both can shift power to "any wheel" using brakes. But as posted above, I think it has to do with TC (which sucks off road) and how the car limits power and brakes spinning wheels.. All of this is neat computer wizardry, but a cheap work-around to real LSD's and lockers... and probably prone to electronic gremlins right when you don't need them. .. My 2c.
 
#22 ·
I thought ELSD and "electronic locking diff" are a marketing way of saying "open diff with brake assist".
The rear ELSD used by QD2, the Eatons EGerodisc "is a hydraulically-operated electronically controlled limited slip differential that provides variable torque up to full axle lock" (quote from eatons website). So it's quite different to the open diff used on the front axle (both front and rear for QT2). Looks like Jeep are using the term BLD (bake lock differential) with reference to the open diffs which is as you describe...

In the wk with QD2 the ELSD was fitted to both front and rear but with the wk2 it is rear only. They reckon the BLD on the front is almost as good. If this is really true then why even fit the ELSD to the rear? I suspect there are sales/marketing reasons at play, and that the ELSD are still better. However as the processing power of the onboard controller for the BLD improves (as apparently it has given a big improvement bewteen wk and wk2 QT2) makes me wonder if in the not-too-distant future there really will be little advantage to the ELSD...
 
#23 · (Edited)
comnjeep you may be hearing ELSD where they are saying brake traction control or ESC or simply traction control.

By the way, the WK2 uses an electric motor now to operate both the transfer case and differential clutches, not the hydraulic pump they have been using for a few years. The hydraulic system needed a bit of wheel spin to get going, annoying the heck out of a few trail riders. The WK2 computer is programed to anticipate tire spin, so the response is instantaneous in most conditions.

ESLD will always have the advantage of getting more power to the ground and less wheel spin. Brake traction converts a lot of power to heat along with wearing out the brakes. Ok for light duty, not so good for heavy duty. Since the rear axle is doing most of the push on up hills where you may need a lot of traction, ELSDs advantages will be felt most there.
 
#25 ·
Why does Jeep advertise open diffs as a 'brake lock differential' ? Tell me if I'm wrong but isn't it still a normal open diff with help from brake traction control?
 
#26 ·
That seems to be a convention in the industry, not only Jeep. They view is as brake traction assisting the differential.. locking one wheel so the dif can provide power to the other... so the term gets turned on it ear.

All WK2s have brake traction control on the front axle. All WK2s with the exception of QD have BTC on the rear. QD uses a limited slip Differential on the rear and no BTC.

ESC (electronic stability control) operates on each wheel regardless and in conjunction with the ABS and brake traction.
 
#28 ·
Thanks for all the explanations.

As I see it with my jeep without qdII, I can lock the center diff only by going to 4lo.. This is probably fine for what I do, but I do sort of wish I could lock it separate from 4lo. I would think that would obviate the need for a elsd in snow conditions for the most part.

I can understand the marketing of the ELSD and "electronic locking diff" being actually just brake assist. Actually, it's ingenious. But It's hard to get the true info on the mechanics of these vehicles sometimes. And the more you know how your car works, the more you can work your car. This isn't just talk either. I've seen pretty expensive AWD vehicles sliding backwards down hills where I live - mainly from TC being overzealous I think.

Thanks again. Good thread.
 
#30 ·
As I see it with my jeep without qdII, I can lock the center diff only by going to 4lo.. This is probably fine for what I do, but I do sort of wish I could lock it separate from 4lo.
I've often wished that too - a locked 4Hi mode (the mitsubishi 4x4 have this).

However, the reason they don't is that the centre diff is also effectively an ELSD (also made by Eaton I think). This means that it can also lock (partially or fully) automagically as conditions require, much like the rear ELSD on QD2 will lock as required (and it does NOT use brakes to do it).
 
#34 ·
Well I'm not so sure a locked center diff is so dangerous if the front and rear are open. I don't see Mitsu's flying off the roadway.

But if the WK2 can lock as needed, or nearly so (80%, no?), I'm all for letting her do her job. Last winter was so mild I never got to really test her out.

4hi locking would be good for when you are in snow as you can regularly go 50-100 miles at say 45 miles an hour without seeing a speck of dry pavement - at least where I live, and 4lo requires the lower speeds or stopping to revert to hi.

I guess the dccd dial on the STi would be ideal but I know that is a different vehicle.

What I get from this thread is the base Overland WK2 is about ready for the trail and I've been contemplating beefier tires and using it more off road versus keeping it strictly for pavement and hwy. So again, this thread helps sort things out a bit. Thanks.
 
#36 ·
I think that's the first time I've seen pics of a WK2 SRT8 off road. How did it go?
 
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#37 ·
Considering the wide, fat, half bald street tires in very loose dirt/sand the AWD system worked well. I was curious and wanted to see how well the AWD would handle a low traction situation. It was fun to experience the system work its magic to try and keep the jeep moving. It is a jeep after all lol, it's in it's DNA to go off road.


Sent from my iPhone 5
 
#40 ·
Good info in this thread. Thanks to the contributors especially Biggie for the video in post #16. (Biggie, Latham is my hometown, BTW!)

At first on reading this thread I was bummed that I did not get QD-II on mine but the explanations here helped, and I know that I'll be okay in almost all situations having QT-II and not QD-II.

Quattrojeep thanks for resurrecting this thread. I may not have found it otherwise.
 
#41 ·
I bought my Jeep Grand Cherokee from a dealer 250 miles away from me. They offered way better incentives than my local dealer.
When I started corresponding with them I specifically told the sales person I wanted one with Quadra Drive not Quadra Trac. When he sends me the vehicle info I called him back and told him it was not what I wanted and repeated myself. He told me it had the offroad adventure package which included quadra drive and emailed me the info on that package.
So I finally drove up and bought the JGC. I chould have done my homework better because I ended up with an Overland with Quadra Trac.
I am so pissed at the sales person and that dealer that does not train their people properly on the products they sell.
The sad thing is if a knowledgeable sales person had educated me on the differences I might have chosen quadra trac anyway; but, I was not given that opportunity.
It is a comfortable vehicle, but I'm still pissed!
 
#42 ·
I bought my Jeep Grand Cherokee from a dealer 250 miles away from me. They offered way better incentives than my local dealer.
When I started corresponding with them I specifically told the sales person I wanted one with Quadra Drive not Quadra Trac. When he sends me the vehicle info I called him back and told him it was not what I wanted and repeated myself. He told me it had the offroad adventure package which included quadra drive and emailed me the info on that package.
So I finally drove up and bought the JGC. I chould have done my homework better because I ended up with an Overland with Quadra Trac.
I am so pissed at the sales person and that dealer that does not train their people properly on the products they sell.
The sad thing is if a knowledgeable sales person had educated me on the differences I might have chosen quadra trac anyway; but, I was not given that opportunity.
It is a comfortable vehicle, but I'm still pissed!
Like many who post here you didn't give much info on your vehicle. AFAIK - QDII isn't available with the V6 and would be standard on an Overland with ORII with diesel or Hemi.
 
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