Please explain why Explorer has AWD and 4wd buttons

I always though that awd meant the vehicle is always in 2wd until it senses a tire slipping and then put it in awd. It can be constantly be going back and forth, that's why it's not as good as 4wd since it is always spinning all 4 tires. Now some awd systems may be way more advanced than others but I think the concept would be the same.

 

4wd doesn't necessarily spin all 4 tires. Unless you have lockers front and rear (or ls at the least), you're going to get a one wheel peel front and back.

 

True but at the end of the day, 4wd beats AWD.

 

Could care less

 

Full time four wheel drive, also called permanent 4WD, (not to be confused with: part time 4WD ) is a system that powers all four wheels at all times and can be used full time on all surfaces including pavement. The additional feature of a differential incorporated into the transfer case makes it possible to use 4WD all the time.
2WD is not available (only part time 4WD offers that option). Each tire creates about 25% of the available torque when the ground is level with a consistant surface. Driver has a choice of a "4-high" (that's your every day setting) and "4-low".

When "4-low" is selected the wheels create substantially more torque (on a Grand Cherokee its 2.72 times more) than in "4-high" - at the same time the vehicle moves at substantially slower speeds (2.72 times slower on a Jeep Grand Cherokee).

Important: "4-low" does not create more traction - it creates more torque and that can be detrimental when the ground is slippery. Slipping tires are more likely in "low" than in "high"! On snowy, icy roads "low" would be a bad choice - some really deep snow, however, puts up so much resistance that "low" is needed to push forward. You see, using 4WD is not an easy task.

The low setting is an advantage for drivers who need to tow and maneuver a heavy trailer etc. and for drivers who at one point or another may want to negotiate difficult off-road terrain, when more torque and/or slower speed is needed.

All wheel drive (AWD) is a system that powers all four wheels of a vehicle at all times as well. Full time symmetric AWD would be the best term to be used. Difference to full time 4WD is that a "4-low" setting is not available in AWD cars. Due to the lack of "low range" AWD vehicles are much less capable in off-road settings than full time 4WD vehicles, but work perfectly well on-road.

Recently some new "automatic" AWD systems have emerged. Fancy names like "Real Time 4WD" or "active AWD" are hiding the fact that they are essentially sophisticated 2WD systems. Automatic asymmetric AWD would be the best term for them. Unfortunately, since they offer AWD only part of the time, some confused magazine writers have called it "part time 4WD" - but that term has been used since WW II for cars like the Willys and Jeep Wrangler and their part time 4WD - the name coming from the fact that 4WD can only be used part of the time (when off-road), most of the time they have to operate in 2WD (on-road).

Here is how they work: Under normal conditions one axle gets 100% of the torque - meaning you are driving in 2WD. During traction loss at the driven axle (could be front or rear) a fully automatic system (hydraulic, mechanical or electronic) makes some of the torque to the axle with traction available. This means you have to lose traction in 2WD on your driven axle first and then the other axle will be added and try to keep the car moving and stable. Once the primary driven axle regains traction and both axles rotate at the same speed again, the system reverts back to 2WD. So, for a moment you had AWD.

Automatic asymmetric AWD is much less capable in off-road settings than full time AWD systems and inferior to full time 4WD. However, automatic asymmetrical AWD is becoming more and more sophisticated and offers pretty much everything consumers expect for everyday (pavement) driving

 

Nice job Nick

 

copy and paste from rubicon trail site

 

Very awesome man.Fully explains what i asked to a T.Thanks bro

 

well i didnt take the time to read nicks book but, haha, basically i've always thought that awd is when on slips (front or back depending on vehicle) the other then engages and spins, 4wd both axles are engaged and spinning, my old explorer had 2wd, 4 auto, 4 low, which was nice for winter driving but in any mud you had to watch out if you just tried to floor it cause the 4 auto would have a big thud when it engaged,

i almost bought another explorer, it was a 5.0 eddie bauer but only had awd so i passed it up

 

Past Explorer's (95+ models) have had full-time AWD and part-time 4WD, with many people confused with what they have. All 1st Gen Explorer's came stock in only 2WD or 4WD.

AWD Explorer's will not have a knob to adjust to 4hi or 4lo. An Explorer with 4WD, will have this knob (or shift lever), and depending on model year may also have an auto setting. This auto setting basically engages 4hi when it feels wheel slippage. Ford used to call it something like Control Trac back in the day, not sure what they call it today.

Anyways, my family has owned both. Father had a '96 XLT 4.0L OHV 4x4 and an '02 Limited 4.6L 4x4, while I owned a '99 Limited 5.0L AWD. In light snow or rain, the '99 AWD was much better, as it always had the 4 wheels engaged, but of course this used more fuel. In mud, heavier snow and off-road, the two 4x4 version were clearly light years better. My '99 had something like a 35% front/65% rear power split, so it was still RWD biased at all times.

The new 2011 Explorer is now only offered in FWD (gasp) or AWD. They offer what Ford calls "Terrain Management", which basically monitors wheel slippage and provides different specs (through adjusting the motor, tranny & brakes) depending on the mode you have selected. Basically it's an AWD system to compensate for those that don't know how to drive in those conditions.

http://media.ford.com/images/10031/2011_Explorer_TMS.pdf

Give me a true part-time 4WD system please.