Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!





Toyota 4WD systems explained

18081838586121

Comments

  • pschreckpschreck Posts: 524
    Since when? AWD implies that the 4Runner doesn't have a two speed transfer case like a Subaru. The new 4Runner is Full-Time 4WD by my understanding.

     

    You guys need to get your terms straight or you're going to confuse people that are reading this forum for the first time and have little knowledge of these systems.
  • steverstever YooperlandPosts: 40,016
    Unfortunately even the manufacturers don't seem to be consistent with the terminology. I would hope that Toyota is consistent within its model lines though. Cliffy has a good summary in the first dozen posts or so.

     

    Steve, Host

    Moderator
    Need help navigating? stever@edmunds.com - or send a private message by clicking on my name.

  • wwestwwest Posts: 10,706
    Is simply an add-on to 4WD capability. Other than being a common "accessory" to many 4WD systems (and virtually ALL of the older ones), having a 2-speed transfer case does not relate in any way to AWD or 4WD.
  • pschreckpschreck Posts: 524
    Then what IS the difference between AWD and 4WD?

     

    I believe that a CENTER DIFFERENTIAL is an accessory to a 4WD system while a TRANSFER CASE is fundamental to a 4WD system.

     

    AWD never (that I know of) has a TRANSFER CASE.
  • wwestwwest Posts: 10,706
    except for marketing differentiation...

     

    AWD systems are presumed to be FULLTIME, but many 4WD systems were, and are, fulltime. I think the "marketeers" wanted to differentiate AWD for 4WD for good reason. AWD is generally taken to mean fulltime 4WD with no driver intervention.

     

    Most traditional 4WD systems, even those with fulltime mode, have other drive modes, thereby require driver intervention.

     

    The new 4runner, for instance, has a RWD mode, an AWD/4WD mode, and a part-time 4WD mode wherein the center differtial is locked.

     

    Disregarding its off-road capability entirely, the 4runner's fulltime system is likely one of the best in the market today.

     

    Oh, sorry, almost forgot. Most transfer cases also have a differential in the form of a planetary gear set. I think, not sure, the term "transfer case" has come to mean a 2 speed gearbox, by default.
  • Am putting together spec's for the '05 Tacoma we want to purchase(4WD, Auto., Off-Road #2, Impulse Pearl, Running Boards(RB), Bed Mat(CJ), JBL Stereo(EJ)...). Edmunds, and KBB list the below option:

     

    VEVSC w/DAC

    Includes Vehicle Stability Control (VSC) with Traction Control (TRAC), automatic limited slip differential, hill-start assist control (HAC) and downhill assist control (DAC). REQUIRES OG or PT or SJ or SN.

    But this is not listed as an option on the buyatoyota site. Does anyone have this option? Is this NOT an option with the vehicle I have described? I'll be doing in-town, occasional snow/ice, and some beach driving - is this package worth $800?
  • stove1stove1 Posts: 53
    It might help a little but I doubt it makes too much difference on snow and ice when you don't have traction. VSC operates by selective braking one of the wheels . What good that will do when you don't have traction on ice ?
  • hank14hank14 Posts: 133
    This thread and others like it should have a mandatory warning label that anyone who reads it should be prepared to become dazed and confused. If someone misuses their vehicle- from tire inflation to fluid type to how to use it's respective 4WD system, it's their own fault. Read your manual. Take a 4wd class. Practice in an empty parking lot, off road, or something. No wonder everyone is so confused. I only keep reading because it is comical. I think I'll stick to a Landcruiser specific forum from now on. Happy New Year.
  • wwestwwest Posts: 10,706
    The only time I can say for sure that my VSC kicked in was when I drove a bit too agressively through a water puddle as I turned left out of a driveway. Obviously the same thing could happen on a rain slicked street or even an oily spot.

     

    No ice or snow required.
  • This discussion thread is like reading a script for Abbott and Costello's Who's on First!

     

    B
  • I just got a used 99 Toyota 4Runner Limited. It has the push button on the side of the 4wheel drive lever and the ability to put it into 4H and 4L with locking center differentials and locking rear diffs button on the dash. Are you with me there? So I believe it is a full time and a part time system. I do understand why not to drive on dry pavement with LCD or the rear diff engaged. I am 23 years old and this is my first 4x4 or truck. I just wanted to make sure I know my system before I go backcountry driving in Colorado.

     

    Let me know if I am wrong:

    I am cloudy on a few things. I believe when I hit the button that just the front left and the back right wheel have power and if the rear loses traction the front keeps the truck moving and that this is called full time 4w drive. If I shift the lever into 4H with locking center differential, than the front and rear will move at the same speed and not allow the front or back to move faster and this is called part time. Does the 4H with LCD make all four wheels have power or is it just still one in the front and back? Whats the advantage with LCD over just the push button mode (full time)? I have a good idea what the locking rear diff does, it basically gives 50/50 power to both back wheels but I always wonder whats going on with the front at the same time. Do the 2 front wheels ever have power at the same time. For instance lets say that I am in 4L with LCD or 4H with LCD, what wheels truly have power?

     

    Thanks for the help. I am just getting started and I find it interesting but it can be confusing. I want to be confident in my ability to execute the right moves.
  • russlarussla Posts: 74
    Let me know if I am wrong:

    "I believe when I hit the button that just the front left and the back right wheel have power and if the rear loses traction the front keeps the truck moving and that this is called full time 4w drive."

     

    full time means that the center diff is unlocked, and if you have open diffs front and back, then only one wheel will spin, if it looses traction (or if two wheels should both lose traction simultaneously, it is possible to spin both one on the front and back) but if 3 wheels have traction and one doesn't, then only one will spin. and you lose forward propulsion. Left or right isn't a factor, it's the traction (or lack of )that determines which wheel spins first. usually if you're already moving, your momentum may carry you to a different spot where the traction is better and the spinning tire may actually start to get traction

     

    "If I shift the lever into 4H with locking center differential, than the front and rear will move at the same speed and not allow the front or back to move faster and this is called part time."

     

    Yes this is part time, the front driveshaft and rear drive shaft, are now locked together, in the a similiar situation to above, the fronts will keep pulling should you lose traction on one rear tire

     

    "Does the 4H with LCD make all four wheels have power or is it just still one in the front and back? "

     

    all wheels get power (torque) until one loses traction, in Part time, you have to lose traction on the front and on the rear to get stuck (one side, doesn't matter which - if you have open diffs)

     

    "Whats the advantage with LCD over just the push button mode (full time)? "

     

    it guarantees that torque gets to the front and the rear, (full time has an open center diff, so you can get stopped with one wheel slipping

     

    "I have a good idea what the locking rear diff does, it basically gives 50/50 power to both back wheels but I always wonder whats going on with the front at the same time."

     

    Yes, the locking rear diff ensures that both wheels turn at the same rate. They're not getting the same power, because one could be on ice and the other on the road, so the torque or power is applied to the one on the road

     

    "Do the 2 front wheels ever have power at the same time. For instance lets say that I am in 4L with LCD or 4H with LCD, what wheels truly have power? "

     

    in any 4wd setting,(full and part time) where all the tires have traction, the wheels "have power" to use your phrase, the problems arise when one wheel loses traction, a normal diff will send the power, to the wheel with no traction, and the wheel with traction doesn't get any.

     

    these days, there are several systems that deal with this issue, electric locking diffs, Limited slip diffs, viscious couplings (a sort of autolocking center diff) torsens, and wheel braking to create torque transfer (not so good for off road)
  • tlcmantlcman Posts: 220
    wheel braking to create torque transfer (not so good for off road)

     

    It works well off road, but the avid offroader should not rely on these, if you are gettting to a camp site 20 miles in on a dirt road that gets tough some times then you will be fine. But for people like me ARB air lockers are great, to get through mud you can not use te Trac system it will de-throttle the engine and you will get stuck, you need to keep the wheels spining a bit to get through it.
  • Anyone have an opinion whether to get a 1999 or 2000 year Landcruiser regarding the 4wd drivetrain. FYI: This will be used on and off-road; with the emphasis on off-road (gravel, dirt, mud, hills, general off-road travel...but not extreme off-road...not Rubicon!)
  • tlcmantlcman Posts: 220
    Drive train is exactly the same... the change did not come until 2003 when they put a 5 speed in. the drive train in the 1991-2002 is the same four speed. With that said, the only advantage is that the front differential splitter for the IFS is a 4 prong in the 00 rather than a 2 prong in the 98 and 99. It may make it a bit stronger, but i dont notice any differnaces. Any land Cruiser will do great off road, no suprises, theve been doing it for 50+ years

    -Mike
  • With part-time 4-wheel drive, is it advisable to run in 4-wheel mode when conditions are "merely" slippery? That is, on a highway where traffic is moving at, say, 30 mph in a snow or ice storm and the road is lightly covered, am I better or worse off in 4-wheel? Would I lose a modicum of control when lane changing because my front wheels are turning at the same speed?
  • wwestwwest Posts: 10,706
    Many of the newer 4WD systems only allow the diff'l to lock in low range. Good idea IMMHO.
  • Hello all- I realize Xreas is not a 4wd system but thought I would post here because of the other previous good posts. I am currently looking for a 2003 or 2004 4Runner- prefer the V-8 2WD version. I am not crazy about the two-tone plastic on the 03 model (the hood scoop is okay). I really want the Xreas suspension/shock system, and know for sure it is on all Sport models, and a stand-alone options on others. I have been looking at 4Runners on Autotrader and calling dealerships, but many of the salespeople have been clueless as to what X-Reas is, let alone how to tell if one of the vehicles on the lot have the system. To further confuse things, some of these same bright people are labelling 4Runners as SR5/Sport in their ads (ones that clearly don't have a hood scoop in the photos). Is there any other way to visually tell is the car has Xreas as an add-on option? I have noticed looking at the interiors that all Sports (and some non-sport models) have a leather shift knob and leather covered steering wheel and others have a hard plastic. Is this the clue I am looking for? Thanks for any input you may have!
  • Thanks russla for the detailed reply. The information is helpful and appreciated. Does anyone have anything to add for a newbie to the 4 wheel drive scene? Any kind of information is appreciated, either specific to my vehicle or knowledge to keep my out of trouble. This coming up summer I am going to do some backcountry driving in Colorado over some mountain passes, just to give you an idea of the terrain I will be cruising. See my first post for additional info.

     

    99 Toyota 4Runner Limited:

    center and rear diff locks and a push button full time mode

     

    Thanks
  • tlcmantlcman Posts: 220
    Hey where are you abouts in Colorado?! I love living there! Anywho, never go out alone, always bring buddys along in other SUVs bring recovery gear, snatch straps and hi lifts a re a good and cheap alternative to a wintch. there is no need to lock your lockers untill you need them or think that you will need them. Do not drive above 10 mph with any of your lockers locked. bring a 12 volt tyre pump in case you have to deflate your tyres for added traction somewhere along the trip.
Sign In or Register to comment.