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Comments
So, don't run anything but LOW speed with lowered tire pressure.
Gas mileage for the V8 is as Toyota states it, as far as the V6 goes I don't know if their stated mpg is while it is in 2wd or 4wd.
Use of the (traditional, historic) 4WD system FULL-TIME would result in damage to the tires and/or driveline in short order.
You get the idea from my post. Regardless of how I named it, I said it could be used on dry pavement.
And any newbie or person who asks a question like that in the end probably could care less about the symantics.
Then you came along and said the "4wd" system can be used on dry pavement.
NOT!
Prove me wrong NOT man.
2 different engines, 2 different 4wd systems, in correct mode both can be used all the time.
If, within the community, we all refer to the full time systems as AWD, and the part time systems as 4WD ONLY, then nobody gets confused and a lot more drivelines live out their warrnaty period.
All I was trying to do was explain in plain english that the 4Runner can be used on dry pavement while employing the "4wd" to someone comparing it to a VOLVO. I doubt anyone considering a Volvo cares alot about the details and technical definitions of the "4wd" system.
All they wanted to know is if the 4Runner can be used on dry pavement in "4wd" like the Volvo. And the answer is yes.
Plus it makes it all the more difficult to explain the vehicles that Toyota makes that truely are AWD.
I believe that AWD has it's place (we own a Subaru) but it's not as a description of Full-Time 4WD.
AWD systems typcially have three open diff'ls but also have some method whereby wheelspin is controlly, limited, automatically, the most common today being the one MB brought to market via the ML320, Brake application at the spinning wheel(s) to allow the engine to maintain a high level of torque output to all wheels, spinning/braked ("virtual" traction) and those with real roadbed traction.
The VC, viscous clutch, is also used in various ways and methods. The purpose is the same, somehow force the engine to maintain a high level of torque available.
4WD system definition: SIMPLE, lock the center diff'l (okay, or the transfer case for those of you with LOW range) and possibly one or both of the others. But now you have a part-time system, it cannot be run extensively on high traction surfaces, can only be used part of the time, thereby "PART-TIME".
Now, there is, or was, a possible third type of 4WD system, one with simply three open diff'ls, PERIOD. These are considered useful for delivering engine equal torque to all four tires when all of those tires have roughly equal traction.
Does anyone have use for this latter version? The manufacturers clearly think not, since not one makes such a road going vehicle today.
2WD/4WD/AWD -- Two-wheel drive means that only the front or rear wheels provide power to the vehicle. Four-wheel-drive vehicles allow the driver to select between two- and four-wheel drive. All-wheel-drive vehicles automatically distribute power in varying degrees to the wheels with the most traction.
Taken from: http://www.edmunds.com/buyguide/suv.html
My Sequoia allows me to choose between 2wd and full-time 4wd and optionally lock the center for part-time 4wd. The traction control tries to stop a spinning wheel with the brakes AFTER SLIPPAGE OCCURS, this is not the same as automatically distributing power in varying degrees like a limited slip does.
The non-virtual limited slip designs in manufacture today, at least the ones economically viable enough to be commonly used, require some level of "windup". One of the two output shafts must turn somewhat farther than the other. Absent this short, momentary, "free-wheeling" capability the driveline would be put under mechanical stress each time you make a reasonably tight and/or quick turn.
The way I read the new VSC equipped 4runner AWD system, they are actually monitoring the steering wheel deflection angle so as not to inadvertantly apply braking to a "seemingly" slipping wheel while turning.
If you want to experience a really "wild" ride get into a high powered sports car equipped with a true "torque sensing" rear differential and go WOT from a standing start into a tight turn.
The torque sensing diff'l will "think" the rear wheel on the outside of the turn has lost traction and will allocate a higher level of same virtually instantly.
No manufacture, not even Porsche, will market a vehicle to the general public with this level of LSD capability.
Look at my definitions again and tell me if more than two definitions are needed, AWD (full-time availability) and 4WD (restricted to low traction surfaces, PART-TIME).
I have little doubt that historically these drive types existed in the marketplace, but I don't know why, except for maybe the racing venue, and except for helping to distribute tire wear evenly I don't see the benefit.
My definitions are meant to apply to multi-wheel drive systems, NOT the vehicle or the way a manufacturer might label of describe the vehicle.
Sequoia's shipped with 4WD are "4WD" vehicles, they have three driveline "modes", 2WD (rear), AWD (brake apportioning), and 4WD (locked diff'l).
ho ho......
The water below New Orleans is less muddy than this discussion ;-)
Sorry, I know this isn't helping, but it's pretty funny trying to keep the distinctions sorted out. Who's keeping the score card?
Steve, Host
A)
2WD AWD 4WD
* * *
Or:
2WD AWD 4-lo
* * *
Or:
C)
2WD AWD 4-hi 4-lo
* * * *
C) not so certain of this one but someone told me that it is available. If you have one beware that ABS will be inoperative in 4-hi.
Exactly my point - and I am enjoying your discussion, although I do think the subject has been beaten to death, over time. In any event, have at it, we may all learn something.
4runner48
Also, the Avalanche has 2WD, 4WD hi and 4WD low, and a Automatic 4WD that engages when the rear wheels slip.
Just throwing my 2 cents into the mix on the whole muddy discussion! :-)
:-)
Hey quick come back bp3959!! :-)
That's a side effect of being a computer addict
All the hubs do are lock your axles to the wheels, the differential would sit between the two axles with another shaft to the center diff(or transfer case). If you let the shaft that goes to the center spin freely in an open differential you could spin one wheel and hold the other still, in a locked diff if you spin one wheel, the other will spin no matter what, the two outputs of that diff a truly locked together and will always spin at the same rate. In a limited slip, if one wheel tries to spin too much faster(it has to allow some slip for turning corners) the diff will try to put some friction to that output so that the power goes to the other output instead of being wasted on a freely spinning wheel. The center works about the same way, one shaft goes to the tranny, and there are two output shafts, one going to the front diff, and another to the rear diff.
There are several different ways carmakers use to engage 4wd, listed below:
Disconnect the front diff from the center and disconnect the front wheels from the axles. I prefer this method as it minimizes moving parts when not in 4wd.
Disconnect the front wheels from the axles only(for example, you unlock the hubs and don't disengage 4wd on the transfer case). This means that your front diff and front axles are still spinning while driving.
Disconnect the center diff from the front diff(usually on vehicles with a transfer case lever inside the truck and hubs you have to get out and lock, people will commonly leave the hubs locked and only disengage the transfer case in the winter so 4wd can be easily reengaged). Same as above, since your wheels are still connected to the front axles, when you drive the front wheels will turn the axles and parts inside the front diff.
Another uncommon way it's done is to disconnect the center diff from the front diff and unlock only one hub, this is usually only used when the front diff is permanently locked.
Not sure about the S-10, but if your Avalanche has a 2wd and 4wd mode, it most likely unlocks the center from the front and unlocks the front wheels from the axles for 2wd. I like this method as fewer moving parts means better gas mileage and less wear. Some vehicles have a seperate lever or button that will lock the center differential, if your truck doesn't have this but still has 4lo, it's possible that it automatically locks the center diff for 4lo or has a limited slip center. You should definately read the manual on that one because if it does lock the center in 4lo, that means it turns into a part-time 4wd setup and can only be used on low traction surfaces such as ice, mud, and heavy snow without causing severe drivetrain damage.
The 4lo is only for use in very low traction like you discribed. I am sure the 4x4 set up is the traditonal set up... Chevy does not seem to really go hog wild when it comes to things. Thank you for the lesson.
Hey you seem to know a lot about vehicles.... I have an issue with the horn in my 2000 Toyota Sienna... it does not work. The fuse is go and the panic button on the remote sets off that seperate horn. I have cleaned the connections on the high and low horns but can not figure out what the issue might be. I am looking to diagnose the problem myself. Might you have any words of wisdom?
Thank you, again!