Biohazard

Can anyone explain the difference between 4WD and AWD. I think I understand, but if someone with a little more technical expertise could explain it to me I would greatly appreciate it. Is one better than the other? What are the pros and cons of each? Is one better in a given situation than the other? That kind of stuff. I have a brother who is AWD crazy and I just can't bring myself to agree with him - I love my 4WD! Our little snow/ice storm last night has spurned my interest.

I did a search, but I came up with 146 threads - i lack the patience for that - sorry.

MTL_4runner

http://www.delalbright.com/Products%...oducts_awd.htm

MTL_4runner

or even http://autos.yahoo.com/consumerreports/4wd.html

Biohazard

takes care of that - many thanks

X-AWDriver

AWD is nice when the roads are just kinda patchy with snow,sand,slush and dry conditions all exist at the same time since AWD can adjust where 4wd can't plus 4wd shouldn't be used on dry pavement. I drive my mom's '99 every once in a while and even up to 10 inches of snow I always just use the AWD mode;much better control with minimal throttle input. AWD also makes it harder for the rear end to come around on you since if the rear wheels slip then the power is diverted to the front and keeps the rear where it should be.

kyle_22r

i love awd on ice and snowy roads...but you can't beat 4wd everywhere else

Los Gatos?

If you're a good driver and take it slow, the main difference is AWD = no low gear.

FirstToy

So AWD (4wd without t-case) is actually 1 wheel drive, with the power able to go to any of the 4 wheels.
4wd with a locking diff is actually 2wd, 1 front/1 back

Is that accurate?

X-AWDriver

AWD means it a split,most likely 50/50 between the rear and the front. If the rear starts to come around with AWD then the power will be reduced to the rear and applied just to the fronts till the rear wheels gain traction again thus keeping the rear end put.

4-RUNNIN' FREAK

This is an old thread, so I'm gonna piggyback on it.

I was just out last night at a local spot for quads and dirtbikes, and I was there with a guy and an AWD Saturn Vue that was having problems where I didn't.

It was very soft mud with deep ruts right after jumps for the quads and bikes he was getting stuck in. He was having trouble with the longer mud puddles too. They have over a foot of water in them, and feel fairly solid at the bottom, but not on the approach or departure where it is all soft and torn up from the quads.

He was telling me in the beginning that he goes to this place a lot and he's never been stuck, and I got stuck once, and he went on how AWD is so much better than 4WD, which I later asked him to explain, and he said it's cause it's a Saturn.

I know it's a Saturn and all, but I'd like to know as well as the links in the first few posts don't work anymore. I read this, http://www.4x4abc.com/4WD101/awd.html, and understand it to a point, but would like a clarification if possible.

I just pushed the 4WD button on the side of the high/low range selector, and went on my merry way, so I figure 4Hi(?). Would this be full time or part time 4WD?

X-AWDriver

AWD is constantly controlling the power to the wheels that slip and diverting that power to the wheels with traction and with true 4wd you have to control the slippage since if you just stay in the throttle then the wheels will all continue to spin til you get off the throttle. Awd you can still stay in the throttle a bit more let the computer help you out while you control the steering inputs. Look at rally cars and how much control they have around switchbacks even when they are paved,you can't get that control from true 4wd but you also can't off road with AWD.

4-RUNNIN' FREAK

That helps.

Never saw an AWD anything out there. Guess that explains it.

Fink

Same thing with my mom's Honda Pilot. That thing rules in the snow and rain but anything else and it blows. The one cool thing about hers is its got a locker in the rear, but it will only let it be engaged under 18mph...anything faster and it automatically disengages. She wants to trade it in for an '05 so she can have 4WD cause my dad and I are the only ones that can get out when it rains really hard because our dirt road is so loosely packed it all just floats away lol.

Fink

X-AWDriver

AWD is also beneficial on plain 'ol dry pavement too under hard acceleration;my Eclipse hit the 60' mark about 4 tenths qucker than a Viper on it's stock rubber and all I had was all season radials.

yoda92

there are many types of awd systems out there. Pretty much the main differences no awd LO and usually awd is a full time thing so you arent usualy abe to switch from 2wd to awd. All wheel drive is meant to be used all the time. I have a subaru wrx and the awd on it is not computer controled its 50/50. It has a center diff that allows the front and rear wheels to spin at different speeds.

LittleRedToyota

AWD in and of itself does not send power to the wheel with the most traction...it evenly distrubues the torque (power) among all four wheels via the center diff the same way a diferential in the axle distributes power evenly to both wheels on the axle.

thus, it also has the same drawback...if one wheel completely loses traction (which means that, no matter how fast it spins it produces zero torque), that wheel will just spin and the other three won't do anything (so they are also get zero torque).

that's why AWD, without a controlling system, is bad for wheelin'. if you lift one wheel or if one wheel hits a spot in a mud hole that has not traction, you are stuck.

(rally cars, however, don't really have to worry about lifting a wheel or hitting mud holes...they are driving on dirt roads...which are a lot like slippery paved roads...that's why rally cars use AWD.)

however, some AWD systems have computer controlled systems and/or limited slip differentials to counter the problem of one wheel losing traction...these systems (some better than others, no doubt) attempt to send power to the wheels with traction.

on www.howstuffworks.com, in the auto section, then in the "under the hood section", they have great explanations of AWD, 4wd, differentials, etc. which include lots of moving diagrams showing you visually how everything works while also providing a written explanation.

4-RUNNIN' FREAK

I already looked at how stuff works, so what would I have? Full or part time? I am getting mixed answers the more I read the archives of YT.

LittleRedToyota

you definitely have a part-time 4wd option...you engage it by pulling the lever into either 4hi or 4lo (or maybe you push buttons, i'm not sure if toyota ever did taht, but, if so, thesebuttons would be labeld 4hi and 4lo).

you may also have a pushbutton AWD option. it might be called full-time 4wd or electronically controlled traction or something like that.

check out your owners manual...should have it in there...if you want help deciphering it, post what it says you have.

4-RUNNIN' FREAK

I don't know where the owners manual is. I push a button and I see the 4 wheels on the dash light up and I can push the gears into 4WD LO. I usuaklly leave it in HI and just press the button.

LittleRedToyota

that sounds to me like good ole part-time 4wd. i don't think they ever made a (non 2wd) 4runner that didn't have part time 4wd (though some also have AWD)...i could be completely wrong about that, though.

if you can find any old sales literature on the web for the 02 runner, you might be able to find the answer there.