Swapping Axles for QD II - JeepForum.com

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post #1 of 48 Old 11-23-2016, 10:04 AM Thread Starter
sgossler
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Swapping Axles for QD II

Hello, I am relatively new to the forum. I have looked around this and other forums and have not found much information on swapped axels from QTII to QDII on a WK.

I Have found a doner vehicle, And I would like to install manual controls, to lock the front and rear differentials independently.

So far I know that they requiere at least a 15 Amp relay, and 12 volts. Also, the swap should be pretty straight forward.

Any Advice? its either this or a lunchbox locker... last trail I drove, QT II hammered the breaks searching for traction. It got me up the trail, but I think it would have been much easier with at least a rear locker...


2005 Jeep GC Limited 4.7 QTII
2.3" RRO lift Bilstein Struts/Shocks 255/70R17 Cooper AT3
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post #2 of 48 Old 11-23-2016, 10:24 AM
monkey6
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Yes, it is possible. I was looking into it for a while, just don't have the funds to pick up the QDII axles right now. Biggest thing is getting the ECU to recognize the gearing change because the QDII has 3.73. I have the 3.7 which has 3.07, not sure what the 4.7 QTII comes with stock. I know the Hypertech tuner for the 3.7 has the option to change gearing. Other issue that I've seen on a previous post where it was done is that the prop shafts from the transfer case to the diffs might have a different bolt pattern at the diff side. Something to look into before tearing it all apart.
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post #3 of 48 Old 11-23-2016, 12:27 PM Thread Starter
sgossler
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Thanks for the feedback. I did not consider different gearing in the difs. I am still negotiating with the scrapyard, to se how much they want for both differentials. I could very well ask for the shafts as well. I will be sure to pay close attention to the bolt pattern.

http://www.wkjeeps.com/wk_specs.htm

According to this website, both 4.7 and 5.7 engines feature a 3.73 Final Drive on both types of systems.

Hopefully they wont ask for too much money. I believe I could be getting them both for close to $500

2005 Jeep GC Limited 4.7 QTII
2.3" RRO lift Bilstein Struts/Shocks 255/70R17 Cooper AT3
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post #4 of 48 Old 11-23-2016, 12:50 PM
derpboss
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I think adding a locker is a much easier option honestly.
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post #5 of 48 Old 11-23-2016, 01:02 PM
board350
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What is the difference in the transfer case from a QTII and a QDII? My understanding was the QDII transfer case differential also contained a auto locking feature when in 4HI but went full locked in 4LO. Also, if the QTII final drive computer is attempting to control the brakes during wheel spin and you induce a locking diff, either QDII or lunchbox locker, isn't that going to cause issues? Just thinking outloud.
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post #6 of 48 Old 11-23-2016, 04:00 PM Thread Starter
sgossler
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It is my understanding, that the transfer case on both QDII and QTII is exaclty the same. As it is the same part number.

Also, differential brake control activates its function when one wheel is spinning faster then the other on the same axle. In theory, once they are manually locked the computer will never know the difference, as both wheels will be spinning at the same speed.

Regarding the aftermarket locker, The best would be an ARB locker, but that is $1,200(locker,Air compressor) + labor. An Auto locker, is much cheaper at $350+/-... but it has its handling quirks, and that is only for the rear.

My option would be close to $600, that is for both axles, with manually activated lockers. Labor should be much simpler as they are suppose to bolt on.

2005 Jeep GC Limited 4.7 QTII
2.3" RRO lift Bilstein Struts/Shocks 255/70R17 Cooper AT3
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post #7 of 48 Old 11-23-2016, 07:07 PM
SSF556
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I believe you also have to get the help of a Chrysler dealer to get the reprogramming done. Also keep in mind that QT2 is not locking the diffs..it is limiting slip. There is a big difference between the two.

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post #8 of 48 Old 11-23-2016, 07:14 PM
guygene
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Truetrac-by-eaton seems like it would be the cheaper option. People seem to love them.

http://4xguard.com/grand-cherokee-20...-by-eaton.html
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post #9 of 48 Old 11-23-2016, 07:37 PM
board350
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That would make sense to me that it would work then. It is my understanding that you are wanting to use independent switches on the dash to just activate the QDII lockers independent of the final drive computer. In that case it does seem to me that it would be easier to just bolt in the donar axles. This baring the drive shaft difference or mounting difference, if any truly exist.

Sent from my XT1096 using Tapatalk
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post #10 of 48 Old 11-24-2016, 09:51 AM Thread Starter
sgossler
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Quote:
Originally Posted by guygene View Post
Truetrac-by-eaton seems like it would be the cheaper option. People seem to love them.

http://4xguard.com/grand-cherokee-20...-by-eaton.html
I believe this is a better option to an autolocker/lunchbox locker. I will defenetly consider it.

2005 Jeep GC Limited 4.7 QTII
2.3" RRO lift Bilstein Struts/Shocks 255/70R17 Cooper AT3
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post #11 of 48 Old 11-24-2016, 09:56 AM Thread Starter
sgossler
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Quote:
Originally Posted by board350 View Post
That would make sense to me that it would work then. It is my understanding that you are wanting to use independent switches on the dash to just activate the QDII lockers independent of the final drive computer. In that case it does seem to me that it would be easier to just bolt in the donar axles. This baring the drive shaft difference or mounting difference, if any truly exist.

Sent from my XT1096 using Tapatalk
Yes, this is exactly what I want to do. Independent switches. I understand it will not be OEM... but i think it gets the job done.

2005 Jeep GC Limited 4.7 QTII
2.3" RRO lift Bilstein Struts/Shocks 255/70R17 Cooper AT3
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post #12 of 48 Old 11-24-2016, 11:32 AM
jimbono
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Quote:
Originally Posted by sgossler View Post
Yes, this is exactly what I want to do. Independent switches. I understand it will not be OEM... but i think it gets the job done.
I like the idea of replacing only the rear axle. If you do this successfully please, please make a thread! I'm very interested.

I imagine it being a little more involved than replacing just a differential, but if it's really as simple as bolting on the new axle and hooking up some switches for manual control that sounds amazing. I'd be super down for that. There are probably a decent amount of qdii axles floating around in scrapyards...

It's my understanding that If the rear tires are spinning at the same speed the qtii won't activate the brakes.

Also, is it true that the new qdii systems have the ELSD rear but only brake activation up front? I think I remember reading that but i might be totally off on that.
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post #13 of 48 Old 11-24-2016, 03:50 PM Thread Starter
sgossler
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Ok, so I am still trying to get the scrapyard to sell me the axles, they seem to have a bit of work before they can dismantel the WK Overland...

I cant insist too much, as if I do, he will jack up the price... I guess. he told me next week he will let me know how much it will be for the parts.. I hope he sells them cheap.

I will definitely make a thread on it. At least to let people know if it is posible or not, and how easy or difficult it is to make the swap. I have a close friend who has a mechanics shop... He will be helping me with the swap.

I am trying to get both front and rear, I know they have the complete WK at the scrapyard... so Its easier for them to just sell more parts at the same time. And better for me to get both rear and front difs now.

It is also my understanding that WK2 QDII have ELSD in the rear only.

2005 Jeep GC Limited 4.7 QTII
2.3" RRO lift Bilstein Struts/Shocks 255/70R17 Cooper AT3
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post #14 of 48 Old 11-25-2016, 09:08 PM
board350
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By the way if you need info on driveshaft bolt patterns, locker signal wire input, pictures etc I'd be glad to get it from mine. Just let me know. I have my skid plates off at the moment so can access it all easily.

Sent from my Nexus 9 using Tapatalk
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post #15 of 48 Old 11-27-2016, 11:48 PM
beemer9
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I upgraded my 2008 4.7L Commander from QTII to QDII several years ago. Look for my thread in the Jeep Commander forum. It's a full blown QDII conversion with the Jeep controlling the ELSD's just like from the factory. BUT you need to get Chrysler Engineering (NOT the dealer) to write a new PCM program for your vehicle. To do that, you need to go thru a friendly Jeep dealer.
Mechanically it required replacing the underbody wiring harness, the front ELSD diff wiring harness, TCM, front diff assy including I think the drivers side axle, and the rear axle assy. EVERYTHING else, xfer case, drive shafts, was the same.
Some people have installed a QDII front and rear axle and operated the ELSD solenoids with rocker switches but I don't know how well that works. The QDII TCM modulates the current and voltage to the ELSDs constantly during use. I don't know what effect applying a constant 12v would have.
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