Four wheel drive or all wheel drive

[drags]

What is the deference between four wheel and all wheel drive, which has more traction or are they equal? Also which has the better gas mileage?
Drags

[R.W.Dale]

What is the deference between four wheel and all wheel drive, which has more traction or are they equal? Also which has the better gas mileage?
Drags

 Generally speaking all wheel drive refers to a system that's active at ALL times with the ability to send power to any or all the wheels automatically without any manupilation by the driver.

 Four wheel drive refers to a system with which the driver selects between 2 or 4 wheel drive ususally these systems also incorporate the usage of a 2 speed transfer case. This gives you normal HI range and a very tractor like LO range for maximum pulling and climbing ability at VERY low speeds.

 The trade off is when all other things are equal with regards to the vehicle an AWD system will use more fuel than a 4x4 system. This is because cause many more heavy drivetrain components are in usage when power is being sent to all wheels.

 usually AWD systems are marketed towards adverse ONroad conditions, snow, ice, water or even high performance.

 4x4 is geared more towards offroad usage, mud, rocks climbing and pulling.

 Some vehicles feature a system that's almost both much like my wife's Cherokee. It has a x-fer case that has a position for 2wd, part time 4wd or AWD then a 4Hi and 4 Lo setting. My wife accidently drove the Jeep all last week in part time 4wd and as a result the MPG suffered by 2mpg for that week.

 

[Empty Quiver]

Depending on the vehicle in question, you may have a front drive with assistance from rear axle or rear drive with assist from front. The transfer case acts more like a limited slip axle on all wheel drive vehicles. Some will not operate over a certain road speed. My experience is with a Expedition which has AWD as well as 4Hi and 4Lo. I live in Mn. and can say that on "normal" snow 4 Hi is rarely needed, if I didn't have it I probably wouldn't miss it. On very slick (read glare ice/ lake driving) 4 Hi is more stable and makes a noticeable difference. As far as mpg goes mfg. says it's negligible. I have no way of comparing, but with as many electric clutches and computerized systems that are employed making this all work, it's a shame if it isn't the same. If  "getting there" is criticle then go with traditional transfer case and locking differentials. For safety and peace of mind AWD is very good. Tires can make more difference than hardware choice in my mind.

[Buckskins & Black Powder]

I'll take a real 4 wheel drive set up any day. I need the option of 4 low.

My sister has a 2007 ford 500 AWD and with a little over 6800 miles, It has had a broken front axle and a tranny replacement, Wiring problems for the AWD.

I dont even like the electronic 4 wheel drive in our f250 but its been good, I just feel safer with the manual hubs and transfer case.

[NYH1]

The differences between the two have already been mentioned. 

We've had  both.  Our 2005 Durango was all wheel drive.  It had AWD, 4WD high and 4WD low.  It had the Hemi (5.7L) and we got 11 MPG in the city and 18 MPG on the highway.  Our 2003 Durango was four wheel drive with the 4.7L V8, it had 2WD, 4WD high and 4WD low.  It was also smaller.  They got the same mileage.  When I towed our four place ATV trailer (about 4,000 LBS.) the 2005 got much better mileage then the 2003 did.  The 2005 is the best vehicle I've driven in the snow so far.  I never really had to put it 4WD.  I did a few times because I was in a foot or more of snow and it made sense to in those situations.

We turned the 2005 Durango in and leased a 2008 Jeep Patriot.  It's AWD.  Most of the time it's in front wheel drive.  If the front wheels start to spin, the rear wheels engage.  It can also be locked in 4WD.  To be honest, it works pretty well.  Gets 20 MPG in the city (this is why we down sized!) and 24 MPG on the highway.

My 2007 Ram is four wheel drive 2WD, 4WD high and 4WD low.  I could have gotten AWD.  I'm happy with it the way it is though.  My 2002 Dakota, 2000 Ranger, 94 F150, 86 Bronco and 86 Ramcharger were all the same way.  Our 2000 Cherokee Sport was the same as krochus's.  2WD, AWD, 4WD high and 4WD low.  I think they called it Select Trac. 

I'd be happy with either.  I prefer my wife has AWD.