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New here, I have been searching for a couple of days now. I removed my front driveshaft on my 2008 mountain edition and as soon as i put it down it started rolling backwards down the driveway. I jumped in and put on the brakes. I started the Commander and when I put in drive it acted as if it was in neutral and started rolling backwards again. I then put it in 4lo and moved it back up the driveway and put on the parking brake at took it out of 4lo. When I put it in park i could hear the gears faintly grinding like the were trying to catch but the rpm's were too high, then finally caught and stopped. It has the QT-II and 4.7 flex fuel. I thought these were RWD or atleast all wheel drive. What am I missing here?

Woody
 

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New here, I have been searching for a couple of days now. I removed my front driveshaft on my 2008 mountain edition and as soon as i put it down it started rolling backwards down the driveway. I jumped in and put on the brakes. I started the Commander and when I put in drive it acted as if it was in neutral and started rolling backwards again. I then put it in 4lo and moved it back up the driveway and put on the parking brake at took it out of 4lo. When I put it in park i could hear the gears faintly grinding like the were trying to catch but the rpm's were too high, then finally caught and stopped. It has the QT-II and 4.7 flex fuel. I thought these were RWD or atleast all wheel drive. What am I missing here?

Woody
Woody;

I have the same model year, power train, & 4WD system as you, the only difference is my XK is just a Sport - not a Rocky Mountain addition - but, I did own a 2008 Grand Cherokee (WK) Rocky Mountain Edition, so, I do know what the Rocky Mountain Edition trim package consists of;

So, the first thing you have to understand is the QT-II 4WD system uses the NV245 2 speed transfer case (same transfer case that the QD-II 4WD system uses) and it is in 4-HI all the time, you NEVER have the ability to switch into 2WD with QT-II.

As far as switching into 4-LOW, you are supposed to be in Neutral, on a level surface with the vehicle not moving, when you drop down into 4-LOW. You are not supposed to put it into your XK into 4-LOW on a paved or cement surface - and definitely NOT when you are on an incline or decline; Furthermore, it's meant for sand, mud and snow - in other words soft substrate, not a hard paved surface on an incline or decline, that's probably why you heard some faint grinding.

Hope this helps.
 

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Discussion Starter #3
I understand that, I guess what I am asking is if the front drive shaft is removed, it should be able to move under it's own power. I believe my transfer case is in need of rebuild because it is only supplying power to the front axle and not the rear unless it is in 4 lo.

Woody
 

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I understand that, I guess what I am asking is if the front drive shaft is removed, it should be able to move under it's own power. I believe my transfer case is in need of rebuild because it is only supplying power to the front axle and not the rear unless it is in 4 lo.

Woody
The NV245 is a torque split full time limited slip All wheel drive transfer case. It must have the resistance between the front and rear wheels to engage. With the front disconnected there is no resistance, so there is no "hook up" between the the two. It sounds like your transfer case is behaving just like it is meant to.And if you replaced the front shaft but removed the rear shaft it would be the same thing. Point of note, as you have found, putting it in 4lo will allow you to move with a drive shaft removed (either drive shaft) because the limited slip is no longer active and the front and rear are locked. Good thing to keep in mind if you loose a shaft on the trail.
 

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Discussion Starter #5
The NV245 is a torque split full time limited slip All wheel drive transfer case. It must have the resistance between the front and rear wheels to engage. With the front disconnected there is no resistance, so there is no "hook up" between the the two. It sounds like your transfer case is behaving just like it is meant to.And if you replaced the front shaft but removed the rear shaft it would be the same thing. Point of note, as you have found, putting it in 4lo will allow you to move with a drive shaft removed (either drive shaft) because the limited slip is no longer active and the front and rear are locked. Good thing to keep in mind if you loose a shaft on the trail.
That is good to know! so what happens if you are on a slick surface like snow and loose traction to the front end, would the transfer case loose resistance and disengage the rear?
 

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That is good to know! so what happens if you are on a slick surface like snow and loose traction to the front end, would the transfer case loose resistance and disengage the rear?
If things are functioning correctly, wheel slip will be detected by the Jeeps ESP through the wheel speed sensors and engage the limited slip of the transfer case, differentials (if QDII equiped) and the ABS traction control. I would imagine that if the Jeep was turned off and some how either the front or rear were on a VERY slick surface a roll away could happen but at that point the jeep would be sliding anyway.
 
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