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tdixon1000 12-06-2010 07:23 PM

quadra trac ll question
I have a 99 grand cherokee ltd,

I would like to know when the transfer case receive a message to go into 4wd, how and where does the front axles auto lock to engage wheels to front drive shaft? My jeep does not have vari lock, so I'm wondering how my jeep auto locks the wheels/axles to the front drive shaft on demand from wheel slippage?

DavidESchiller 12-06-2010 07:56 PM

Re: quadra trac ll question
if it's a Limited with Quadra Trac II, it's full-time 4wd. so the front wheels are always engaged.

tdixon1000 12-06-2010 08:01 PM

Re: quadra trac ll question
Ok, I wondered why when I jacked up the front and turned one wheel the other turn in the other direction, thinking the auto hub/axle lock was stuck on, but I guess not

so anyhow, my front wheels while in 2wd will always be turning the front drive shaft and carrying all that load thru the differential?

tdixon1000 12-06-2010 08:13 PM

Re: quadra trac ll question
or are you saying the TC is always driving all four wheels but only transfering torque from the back to the front?

DavidESchiller 12-07-2010 05:59 AM

Re: quadra trac ll question
here, give this a shot

Frango100 12-07-2010 02:34 PM

Re: quadra trac ll question
In respect to driving the front axle, Quadra Trac II and Quadra Drive work the same. The "secret" is the progressive coupling inside the T-case. This coupling is activated by a pump rotor and case assy. The pump rotor is driven by the front axle and the case by the rear axle. As soon as there is a speed difference between the 2 axles, the rotor and case will have different speeds and the pump will give a pressure output, which activates the coupling and will supply torque to the front axle.
When the coupling is not activated, the front wheels will indeed turn the front drive shaft all the time and ofcourse this will give some mechanical losses.
The fact you where mentioning about when the front of the car is jacked up and you turn one wheel, its normal that the other wheel turns the other way. This is happening in the differencial and is in fact the reason that the differential is there. Because when you make a turn, the inner wheel will have less speed then the other wheel. If the drive would be riggid, one of the wheels would start slipping, because they want to turn with the same speed. The differential compensates for that.
You did also mention the Vari-loc, but that one is inside the differential and can transfer the torque to the wheel with the better friction to the road, in case the other wheel slips. The Vari-loc is in both differentials, but each only works for its own axle. These are installed in Quadra -drive Jeeps.

GiggityGiggity 12-08-2010 07:39 AM

Re: quadra trac ll question
^this guy knows waaaaaay too much. lol

Good work Frango!

tdixon1000 12-08-2010 07:29 PM

Re: quadra trac ll question
yes very nice,

Another question I have is, does my 99 Jeep Grand Cherokee ltm quadra trac ll have hydra lock in the front differential?

I believe the system is called the Dana super 30?

Frango100 12-08-2010 08:01 PM

Re: quadra trac ll question
As far as i know there will never be a Hydra-loc or Vari-loc in the front differential for Quadra-trac II Jeeps (seems that Hydra-loc is the manufactures name, which is called Vari-loc by Jeep)
There seems to be some Jeeps with Quadra Trac II which came from the factory with a tow package, which has a Vari-loc in the rear diff only, but i have never heard from anybody who has this.

tdixon1000 12-09-2010 07:21 PM

Re: quadra trac ll question
What I am trying to do is figure out how my system works and what systems I have within my front drive components, because I have a problem, this is what I have

when It snows and I'm driving in it and allow my wheels to slip with considerate amount of power, the front end axel or at least that is where the noise is coming from pops and or clicks, as if something is giving under load within the front drive line.

This only happens with load and wheel slippage, I can only assume only when the TC asks for torque to be applied to the front wheels. It does not make this noise while turning sharp or in cruse or acceleration without wheel slippage.

Because this only happens with wheel slippage and the noise is coming from the front I am assuming front drive line.

My Jeep has 162K on it and has worked great for me up until now with this noise. This noise has progressed from last winter from 1-2 clicks with more load to now 3-4 clicks with less load applied.

I'm going to open up my differential this weekend to take a look at the gears, and also look at the U-joints in the front drive shaft. Other than that I don't know what it can be, I know the CV's are fine as they don't pop during tight turns and I just put new boots on them 4 months ago and they looked fine along with the old boots.

Any Ideas ?

Frango100 12-10-2010 11:14 AM

Re: quadra trac ll question
Your story sounds good, keep us updated on what you will find. The problem is there when the progressive coupler is engaged, so there must be some play somewhere in between the T-case and the front wheels, which causes the noise. I would also check the mounting bushings of the front axle, when you are down there.

tdixon1000 12-11-2010 09:41 AM

Re: quadra trac ll question
I'll be under the jeep with the creeper, and opening up the differentail to look at the gears today.

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