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I have the 06, 4.7 V8 with 4X4. Is it true that these Jeeps are in 4WD all of the time? If so, why? It doesn't seem necessary to me. Wouldnt it waste more gas having it in 4WD all the time?

The whole system is a little foggy to me. I know that the standard 4WD kicks in when the vehicle sense instability in the road, and then there's traction control and I also have the 4WD Lo which I also don't understand very well or what circumstances I would/ Should use it.

If anyone wants to break it all down for me, I would definitely appreciate it.
 

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There is a lot of info on the forum about the 4WD systems and how they work. Do a search for quadra, quadra-drive, and quadra drive. The owner's manual explains when to use 4LO.
 

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I have the 06, 4.7 V8 with 4X4. Is it true that these Jeeps are in 4WD all of the time? If so, why? It doesn't seem necessary to me. Wouldnt it waste more gas having it in 4WD all the time?

The whole system is a little foggy to me. I know that the standard 4WD kicks in when the vehicle sense instability in the road, and then there's traction control and I also have the 4WD Lo which I also don't understand very well or what circumstances I would/ Should use it.

If anyone wants to break it all down for me, I would definitely appreciate it.
Your XK is full time 4 wheel drive. So if your in an area that gets snow, all you have to do is start your Jeep and drive. You dont need to worry about shifting into 4wd or anything. If you every were to decide to go off roading or any where off the pavement where you might need more traction you can put it in 4 low which locks the transfer cause and multiplies the torque 2.71:1
 

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Find yourself a winding gravel road, then drive it at 60 MPH with first, a two wheel drive rig, then the Commander. Actually, do that test the other way around, as you will almost certainly wreck the 2WD rig. :) The Commander will seem to be held solid to the road like Velcro are on the tires, where the 2WD will be very hard to control.

There is a center differential in a full time 4x4. That allows slippage between the front and rear, as well as side to side with the axle's differentials. There are THREE differentials in a full time 4x4 rig.

Low range locks the center differential together, mainly because the huge torque gains will easily overcome (snap/break) drive shafts or axles. The low range on a Commander is almost 3:1, so axle torque loading can triple. The front and rear are locked together to spread that high torque out, so turning on pavement causes binding because the tires can't slip and release the tension. That's why low range is only for off-road.

Quadra Drive II has computer controlled clutches in BOTH axles AND the center differential. That system can apply torque to a SINGLE tire when needed. Jack up the rig and leave one tire on the ground, and it will pull itself off the jacks.

Quadra Trac II is the same system except has a lockup clutch in the center differential only. The axles differentials do not lock, but have braking traction control instead.

Quadra Trac I is a full time 4x4 system with no low range or locking differential clutches.
 

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I went back and re-read your 1st post. I'm guessing you have the Quadra Trac II system. (QT II)

That's a full time 4 wheel drive system. All tires are driven, and torque shifts around as needed through three differentials. A differential has a set of gears which allow one tire to spin faster, such as during turns because your inside tire track circle is smaller than the outside track.

The system has braking traction control, which means if a tire slips, the brake's ABS system individually controls the spinning. In reality, a wheel/tire will "pulse" (start/stop) when it's up in the air. (I've done enough extremes to get tires hanging in the air) When climbing loose dirt on a steep hill, the system will hardly disturb the dirt. There's NO throwing dirt like older 4x4's.

Jeep has a system called ESP. (Electronic Stability Program) The computer has G-force sensors, and uses the ABS braking to control each wheel as needed. That's one of the reasons a Commander is so rock-solid on loose dirt or gravel, it can corner brake to keep you from screwing up. :) You can't skid because IT will take over, pull the throttle away from you, (drive by wire) and brake individual wheels to keep you in control. (It also has steering input sensors, so "it" knows what you're trying to do) When the traction control or ESP kicks in, you hear a buzzing sound which is a rapidly pulsed braking action.

The drive-by-wire system will also remove your throttle input when needed on climbs, so even mashing to the floor, you can't spin the tires. You have to turn off the system before you can hot-rod off-road. If you're not used to what it does, you get the impression it's "gutless" and doesn't have enough power.

The QT II has a clutch pack in the transfer case center differential. If tire slippage is too much from front to rear, that locks up, much like the ABS on a wheel. It's much like ABS for the front to rear axles, rather than each corner. It's pretty unstoppable, and as I found out in Moab Utah, the Jeep will do things beyond your level of comfort. (Including literally drive up a 45 degree ditch bank) It will drive up slick rock that's too steep to walk up, and I kid you not.

Other Jeep exclusives, are things such as the side air bags. Most vehicles, the side bags pop out and then deflate in a crash. The Jeep's ESP system's G-force detectors will keep those bags inflated until you stop moving, because chances are good in an off-road crash, (It is a Jeep, after all) you're going to be rolling down a hill rather than just flop over and stop like most SUV's.

Other little things like the windshield washers: EIGHT nozzles and 2 gallons worth of reservoir. In a Jeep, your mud plastered windshield can get blasted clean, where 98% of other SUV's have a couple of pathetic streams and that's it.

So, even a "soccer mom" version of a Jeep is STILL much more off-road oriented than other SUV's.
 

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Find yourself a winding gravel road, then drive it at 60 MPH with first, a two wheel drive rig, then the Commander. Actually, do that test the other way around, as you will almost certainly wreck the 2WD rig. :) The Commander will seem to be held solid to the road like Velcro are on the tires, where the 2WD will be very hard to control.

There is a center differential in a full time 4x4. That allows slippage between the front and rear, as well as side to side with the axle's differentials. There are THREE differentials in a full time 4x4 rig.

Low range locks the center differential together, mainly because the huge torque gains will easily overcome (snap/break) drive shafts or axles. The low range on a Commander is almost 3:1, so axle torque loading can triple. The front and rear are locked together to spread that high torque out, so turning on pavement causes binding because the tires can't slip and release the tension. That's why low range is only for off-road.

Quadra Drive II has computer controlled clutches in BOTH axles AND the center differential. That system can apply torque to a SINGLE tire when needed. Jack up the rig and leave one tire on the ground, and it will pull itself off the jacks.

Quadra Trac II is the same system except has a lockup clutch in the center differential only. The axles differentials do not lock, but have braking traction control instead.

Quadra Trac I is a full time 4x4 system with no low range or locking differential clutches.

Adondo,

I think the info you posted about the QD II having computer controlled clutches in the center differential is incorrect. The reason I say this is because I blew my transfer case wheeling at Rausch Creek almost two years ago and replaced it with a Transfer Case out of an 05 Hemi QD II Grand Cherokee. The transfer cases were identical when we took them apart. The only wiring that goes to the transfer case is for the shift motor to engage the 4 Low. I had to take the HEMI Transfer Case apart because the front output shaft seal had a leak right off of the shelf from the junk yard. Only the rear output shaft seal can be replaced without ripping apart the entire transfer case. Both Transfer Cases are NV 245J's. So that leads me to believe the way the transfer case works in QD II and QT II is the same and that the only difference is the QD II has the ELSD in front and rear.




You can see it marked 05 WK right on the case. The WK it came out of had an electrical fire under the hood and they still had it at the junkyard when I picked up the Transfer case.














 

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You mean all this time I've been putting that overpriced limited slip additive in the X-fer case for nothing? Whom do I sue? :D I feel cheated now.
 

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Im going to do some more research now. I might call the dealer and see if they list the same part numbers for the transfer case in the 4.7 liter and 5.7 liter. I have had this HEMI WK transfer case in my XK for almost two years now.
 

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Yes, QTII and QDII use the same transfer case.
 

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Adondo, exactly what limited slip additive were you putting in the transfer case. The same stuff you put in the front and rear differentials?
 

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You mean all this time I've been putting that overpriced limited slip additive in the X-fer case for nothing? Whom do I sue? :D I feel cheated now.
My owner's manual does not require additive for the transfer case.
 

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haha yeah i hope he hasnt serviced his transfer case many times. Just pissing money away!
 

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So how exactly does the NV 245 transfer case work in 4 high to transfer the power to the front end when needed?
 
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