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Toyota 4WD systems explained

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Comments

  • intmed99intmed99 Member Posts: 485
    The ATRAC/VSC system is very reliable...as reliable as ABS itself!! In simplification, the system is all connected to ABS system. If you off-road a lot, you may wear out your brake pads more...no system is perfect. At least, it is still cheaper to repair than bursting a CV joint or axle, as can happen with lockers.
  • pschreckpschreck Member Posts: 524
    Time to play. Well, after work.
  • pschreckpschreck Member Posts: 524
    Big snow in DC today. I was supposed to come to the Washington Convention Center for a expo today, but the guys on the news said to stay away. A bummer as I was looking forward to the adventure of a two hundred mile (round trip) drive in this kind of weather. Am I nuts?

    Do you think you'll get a new 4Runner to play with in the snow or does your dealership frown on that sort of thing?
  • wishnhigh1wishnhigh1 Member Posts: 363
    does the traction control system on the new 4runner cut power when wheels start to slip?
  • intmed99intmed99 Member Posts: 485
    The 4wd system on the 4Runners ('01-'03) does NOT de-throttle you IF you lock the center differential.


    You can read more about it here:


    http://www.toyota-4runner.org/showthread.php?s=&threadid=12


    Enjoy!

  • mjs504mjs504 Member Posts: 18
    Just got home from work in NYC in 6 inches of snow. The HL performed great. In spite of what that know-it-all wwest maintains, the HL AWD system did GREAT!
  • dimatteodimatteo Member Posts: 1
    I've purchased a 2003 AWD 6cyl Highlander recently in September and I'm trying to figure out the snow button use. I don't have the limited slip or VSC. I've been reading the posts on that topic but still don't have a clear understanding of what it does exactly and when the proper time is to use it. Yesterday I drove home with no problem using the snow button and was in Drive (L) for much of the time. The manual does not really give an explanation. Can anyone offer some detailed advice? Thanks.
  • hicairahicaira Member Posts: 276
    I could be wrong, in regards to the HL, but in my Land Cruiser, which also does not have VSC, the snow button does two things: 1. Starts the car in 2nd gear, not first and 2. Changes the transmission shift points to upshift at lower RPM's (reduciing the likelyhood of wheel spin).

    HiC
  • toyotakentoyotaken Member Posts: 897
    hicaira did a very good job of explaining that well.
  • wwestwwest Member Posts: 10,706
    Can't say for sure all around, but the one on the GS300 not only started out in 2nd, it also modified the engine torque perfromance parameters.

    Pretty sure my RX300 does the same thing, engine doesn't seem at all peppy in snow mode.
  • cliffy1cliffy1 Member Posts: 3,581
    I missed a few days there. No, I didn't get to play with a Runner during the recent snow. I was off that day and was having my own fun in the Tundra. There were several times I wanted the Runner's 4WD system and I went sideways a few times (nearly bald tires probably had a lot to do with that).

    I did just sell a Limited 4WD to a friend of mine and he reports that it did extremely well. He used to work at a Toyota dealership in F&I so he thought he knew all about the truck. He refused to allow our salesperson to review the proper use of it and he now regrets that. The traction control system startled him and he had to call me to figure out how to engage the 4WD system. He felt pretty dumb when I told him it was always in 4WD.
  • xman1035xman1035 Member Posts: 52
    I purchased a brand new 2002 Sequoia SR5 4WD and the 4WD system on this vehicle is AWESOME. What an improvment over my brother's 1998 Toyota Land Cruiser! Toyota did a great job on it and thought about everything. My wife feels especially safe when driving in foul weather.

    I had to explain the 4WD system to the fleet salesman and he thought that all the 4WD systems on the all the Toyotas were the same.I hope that in the future that Toyota will include this system on the 2004 Tundra.

    Cliffy, any info on what Toyota will be introducing in 2004?
  • wishnhigh1wishnhigh1 Member Posts: 363
    sorry, another question...

    RE the pre-98 Land Cruiser...is there any otrque transfer devices for the front and rear axles. I know there is the differential lock for the center, and I know that there isnt any trick front or rear differentials. Is there a traction control system or VSC to control wheelspin?
  • intmed99intmed99 Member Posts: 485
    Before 1998, there is NO VSC or traction control. In fact, i think the TLC/LX470 was the first Toyota SUV to get traction control and VSC in 2000. Before 1998, there was a rear axle locker available. In addition, you can get a front locker too (i think).
  • cliffy1cliffy1 Member Posts: 3,581
    Xman, you're not the only one who wants this on a Tundra. I own a Tundra and am buying a new one today (my lease is up on the 2000) and it annoys me it isn't there. I have no idea when the 2004 will be out but I am looking forward to it. The 4.7 does fine for me and I never have people in the back so I don't mind the current cab.

    Wishin, there was an option for front and rear locking differentials on the pre-98's and locking rear on the 98 and 99. With an IFS, they had to drop the front locker. Both were dropped when the VSC based system came out in 2000.
  • hicairahicaira Member Posts: 276
    ...and no front-to-rear torque transfer either. It was either open or locked.

    HiC
  • pfestus1pfestus1 Member Posts: 3
    Hi, I am looking at a 1994 TLC that is up for bid at my credit union. It has 160000 miles, is very clean, and drives great. The owners manual mentions "locking differential switches" that would be on the dash, but this one has the blanks but no switch. I assume it was an option. So my question is that with out locking differential, and full time 4 WD, how will it do in high range when the snow gets deep, and the going gets rough? I know I'll have low range to go to if it gets really rough. Thanks for any knowledge.
    Hank in Copper Hill, VA
  • xman1035xman1035 Member Posts: 52
    I believe that the 1994 TLC came standard with locking differentials. Check out this link, it has some info on the 1994 TLC. http://www.internetautoguide.com/reviews/1994/1994_Toyota_Land_Cruiser.html
  • pfestus1pfestus1 Member Posts: 3
    X-man, thanks for that link. It did mention locking differentials, and anti lock brakes. I am assuming they were both optional as the TLC I am considereing does not appear to have either. The manual mentions dash mounted switches to lock the differentials, but there are only blanks where the switches should be. I wonder what kind of performance I can expect with out the option to lock the wheels together when it gets real bad out there?
    Hank in Copper Hill, VA
  • idahodougidahodoug Member Posts: 537
    You won't have any trouble getting around on roads no matter how deep the snow is. The ability of the 80 series to remain mobile will be limited by your tire choice long before it requires you to go to a low range to move. If there is no switch to the left of the steering wheel on the dash, you don't have the optional lockers on that vehicle. However, they are of limited use on road in deep snow - not their intended purpose at all. Whatever you can traverse in a locker model on the road, you can also traverse in a non-locker model.

    You cross posted this to another board, and mentioned it was a repo. For an expensive and complex maintenance vehicle like the 80 this is generally a bad thing. By the time a vehicle is reposessed, it has not had payments for a LONG time. By the time THIS stage has been reached, the owner generally ceased maintaining it for quite some time. So, I'd check carefully for signs of neglect that would cost you a bundle, and I'd not pay anywhere near the market value for a distressed rig like this.

    IdahoDoug
  • xman1035xman1035 Member Posts: 52
    I had a 1993 Toyota Land Cruiser and was an awesome vehicle until it was stolen. Make sure that the LC does not have the GrandTek tires on them. Those tires are okay on the road but do poorly offroad especially in mud. You will have to replace the tires. Try to get a complete check on the vehicle's history by checing the vin number. There are a lot of services that will do it on the Internet for a fee.
  • onyeiiionyeiii Member Posts: 25
    I took the opportunity yesterday to drive my new (~3500 miles) '03 sport 4Runner yesterday in some fairly heavy mud yesterday to see how it faired. I was very impressed for the most part, although I regret not studying up on the various bells and whistles before heading out. I reread the owners manual this morning, and found out some of the things I learned the hard way yesterday - i.e. lock the differential BEFORE getting bogged down in the mud :) Also found out that the VSC will ring bells if you're going to skid (which pretty much became continuous in the muck and mire).

    Question: I kept hearing a sound, fairly loud, coming from the front drivers side. The best way to describe it would be a spring releasing and flopping around a bit before coming to rest. You ever play with a spring door stop when you were a kid? If so you know what I'm talking about. Any ideas if this is normal, and, if so, what would be causing it? I *think* I only heard it when the skid or traction control was engaging, but I'm not positive about that.

    Another question - the VSC disengages when the differential is locked (which kills the skid alert bell, thankfully). Does the traction control also turn off?

    TIA - this, and all the Edmunds boards - have been very informative and interesting. I appreciate the time and effort people are taking here. I only wish I had known about this before buying my new car.
  • cliffy1cliffy1 Member Posts: 3,581
    That noise you are hearing is the ABS system. The brakes are pumped rapidly at whatever wheel is slipping and it makes that grinding/clicking noise. It is very normal.

    I'm curious about your experience with the 2003. Did you ever manager to get stuck with this system without locking the center differential? Had you read this topic and the description of how the torsen center works and how the A-trac system functions, do you think you could have avoided getting stuck if you did?

    The reason I ask is this: I am concerned that a lot of complaints and problems could be avoided if Toyota did a better job of explaining the system to buyers BEFORE they get into trouble. It is a pretty fool proof system but many folks get concerned about all the clicking and whirring noises and back off the throttle which allows them to bog down and get stuck. I'd like to hear your opinions on this.
  • tidestertidester Member Posts: 10,059
    I only wish I had known about this before buying my new car.

    We'll still be here when you're ready for your next purchase! Meanwhile, folks here are very friendly and helpful and we'd all like to hear about your experiences.

    tidester, host
  • onyeiiionyeiii Member Posts: 25
    Thank you for your response!

    Concerning the sound - I wouldn't describe it as grinding/clicking - it does sound very different from the ABS on my previous vehicle (2000 Audi A4). If/when I hear it again I will try to determine if it is connected to braking or not.

    I did not get stuck at any time with the center differential locked - in fact, once locking it, I was able to become unstuck with no problem. I was a little concerned about engaging it at the time because I didn't want to come to a complete stop and lose all forward momentum. And, yes, I had read the information on here about this issue when I first got the truck (about 4 weeks ago) but the details had gotten lost in the information overload. I certainly don't fault Toyota for this - I had the information I needed, and it is my reponsibility as the owner of the vehicle (or any tool) to learn how to use it properly. Toyota covers much of this in the owners manual - it could be better written, with perhaps a table showing the various configurations and applicatons of 4HI and 4LO, with and without the locking differential, but the information is there.

    BTW - I am not a dedicated off-roader - I just like tooling around in the woods when the opportunity arises. Someone with more skills or experience may not have had any problems at all. I was very impressed with the ability of this vehicle - it can handle much more than the driver would attempt.
  • toyotakentoyotaken Member Posts: 897
    This is from personal experience when I took an '03 V8 4Runner out in an area that has alot of mud a couple of weeks ago. It's a construction area that they cleared the land and with all of the rain and snow recently, it has about 4" of mud over an area about the size of 2 football fields.

    With the center diff open but with the Torsen working, I was able to move through the muck, but with difficulty. As described above, the VSC and TRAC systems were working almost nonstop. It was VERY slow going and almost impossible to get any forward momentum, so all forward progress was through traction. Turning was also very slow.

    With the center diff locked, the VSC is disabled, but the TRAC stystem is still active, but is allowed to let the wheels spin a bit more than when the diff is open. Moving, turning and keeping momentum was MUCH easier. I was able to make it up and down 10%-15% grades with no problem at all.

    The biggest difficulty that I found was that, at least in situations with mud, the constant transferring of power front and rear and side to side in both front and rear with the application of the VSC was sapping too much power. With the VSC disengaged, the additional wheelspin needed to dig down to solid dirt and just the TRAC system distributing power left and right accordingly was MUCH more effective.

    Hope this helps.

    Ken
  • intmed99intmed99 Member Posts: 485
    When i off-road and with ATRAC working...all normal. That is just how the system sounds when it works.
  • idahodougidahodoug Member Posts: 537
    Just a general comment on mud. Unlike any other surface, traversing mud deep enough to slow progress requires sustained wheelspin to clear the treads and displace the loose mud atop the firmer surface below. Without mud tires, the treads will likely not clear even with wheelspin and progress will be sketchy at best.

    With electronics limiting wheelspin, this spells poor mud performance even with quality mud tires.

    IdahoDoug
  • mrwhipplemrwhipple Member Posts: 378
    With the new V6 multi-mode system (4runner), is the 4 wheel traction control affecting all 4 wheels when the system is in the 2 wheel drive mode, or only in 4 wheel drive mode?
  • intmed99intmed99 Member Posts: 485
    When you're in 2wd, the traction control system is ONLY on the rear axle...it will not modulate the front brakes.

    However, VSC is always ON until you lock the center diff.
  • mrwhipplemrwhipple Member Posts: 378
    Thanks for the info on that.

    I could see leaving the V6 model in 4WD all the time to have the traction control working to its full potential.
  • wwestwwest Member Posts: 10,706
    And then maybe not....

    Many "true" 4WD vehicles still bias the torque to the rear, including the new 4runner. That obviously makes it somewhat unlikely that it will be the front that "first" spins out/loose. And remember that part of the traction control "activity" is to dethrottle the engine when/if necessary.

    You no doubt are aware that most modern day electronic traction controllers, ECUs, will apply the rear brakes, even differentially if the/a rear wheel(s) loose traction.

    A careful design/consideration of the Trac ECU firmware might result in that not being the case at the front. A designer would certainly have second thoughts about using front differential braking, that might result in steering wheel "feedback" strong enough to yank the steering wheel right out of an unaware someone's light fingered grip.

    Think about it, how is traction control implemented with ONLY FWD? Do they use the brakes? Differentially?

    Or do there follow the clearly safer, more conservative, design path and simply dethrottle the engine on front tire slippage on FWD?

    By running your vehicle in 4WD all the time the only result may be simply lower fuel mileage and increased wear on that portion of the driveline.
  • buffalonickelbuffalonickel Member Posts: 113
    The manual says to drive the vehicle in 4WD for about 10 miles a month. My old PU had locking hubs which needed locking for about 10 miles a month in order to lubricate. But locking the hubs isn't like putting the whole transfer case into 4WD. So if I drive in 4WD in dry weather, doesn't that just wear down everything for the simple task of lubricating the axles?

    B
  • mrwhipplemrwhipple Member Posts: 378
    It shouldn't put much wear on the system. The Toyotas are pretty stout. There is less bind due to the open center diff. Overall, I don't think it's much different (with the exception of being able to switch in & out of 4WD) than the system on the V8 models and those are permanent 4WD.
  • wwestwwest Member Posts: 10,706
    Wouldn't put the drivetrain in much of a bind and would thoroughly lubricate everything. The only problem might be significantly differing tire circumference F/R.
  • intmed99intmed99 Member Posts: 485
    Isn't regular tire rotation going to solve that problem of differing tire circumference??
  • toyotakentoyotaken Member Posts: 897
    The slight difference due to tread wear will not make enough difference for most low tire preasure warning systems that are designed to measure tire rotational differences to pick up on. Please correct me if I'm wrong, wwest, but I think he was implying using vastly different tire sizes altogether. e.g. 15in wheels with 65 series tires in front with 16 in wheels with 80 series tires(for example only, not recommended or likely).

    Hope this clarifies.

    Ken
  • wwestwwest Member Posts: 10,706
    Unrepairable tire flat on my 92 Jeep, put spare on ground, "used" tire as spare, purchased new tire. Result was two new tires on the rear, 17K mile tires on the front.

    Wouldn't readily go into 4WD because of differing circumference F/R.

    I stopped rotating tires when the warning came out about cross-rotating radials, never resumed. And I never rotated the spare anyway.

    And how did low-pressure warning systems get in here, the only one I know of, of that type, is the Alero.

    The discussion, I think, was regarding the potential for drivetrain damage from driveline wind-up due to differing tire circumference F/R.
  • intmed99intmed99 Member Posts: 485
    J/K. You '92 Jeep has part-time system, right?? I don't think wheel size differences mattered.
  • wwestwwest Member Posts: 10,706
    92 Jeep drive modes. RWD, AWD (full-time), 4WD (part-time).

    This "thread" started when someone asked (paraphrasing), "will it damage my drivetrain if I engage "part-time" drive mode for ten miles on dry pavement every so often as recommended to keep all the parts lubbed up?"

    My response was "not if those ten miles are relatively straight and you don't have significantly differing wheel/tire sizes F/R".

    Significant might mean new tires on the rear vs 17K on the front.

    F/R Wheel/tires sizes "matter" when you're trying to dis/engage the two splines (un/lock the center diff'l) with differing rotational rates F/R.
  • intmed99intmed99 Member Posts: 485
    You're taking things a bit to the extreme...the original poster said nothing about having the front tire with 20,000 miles while the rear is brandnew.
  • wwestwwest Member Posts: 10,706
    Was asking about possible problems that might arise from running a locked diff'l system on some sort of schedule to keep things lubbed up.

    I could have advised not to do any tight, nor continuous turning, but opted for go "straight" instead. The only possible problem that might arise from my "straight" advice is if there is some significant level of F/R tire circumference difference.

    I try my very best to not give bad nor incomplete advice.

    If you can think of any other possible problems then please throw them in here.

    73's
  • mikej13mikej13 Member Posts: 2
    I am confused. Here is what I believe:

    The V-6 2003 4Runner when put into 4 wheel drive is the same as the V-8 is in Full Time 4 Wheel drive. It is safe to leave it in 4 Wheel Drive continually with no concern about damage (not required to be on a slippery surface).

    If you feel the need, you can push the button on the left side of the dash and lock-up the differential (cancels VSC). I believe this requires that you are on a surface where your tires can slip some.

    If I am correct, I don't understand the concern about placing the V-6 into 4 Wheel Drive at least once a month (You should not require to lock-up the Torsen differential). It is a full-time 4 Wheel Drive system that you can engage/disengage as you desire.

    AM I CORRECT??? I don't bother asking the dealer because they have not answered one question correctly yet!

    Thanks in advance for your help and clarification.
    Mike
  • wwestwwest Member Posts: 10,706
    The Toyota literature itself reads in a very confusing manner on this subject, V6 vs V8 drive types.
  • intmed99intmed99 Member Posts: 485
    Yes, it is safe to leave your 4wd system in full-time.

    However, IF you choose to use 2wd mode most of the time (as i do), then you should run it in 4wd for 10 miles/month. This also applies to the older 4Runners with part-time 4wd system.

    Yes, do NOT lock your center differential on dry land.
  • cliffy1cliffy1 Member Posts: 3,581
    The confusion actually lies in the fact that I think the question was about an older Runner that did not have the Active-Trac 4WD system. On those models engaging 4WD on dry pavement can be a problem if you turn a corner.
  • wwestwwest Member Posts: 10,706
    turning a corner!

    You can easily damage portions of the drivetrain of a AWD/4WD with the center diff'l locked with an extended drive, more than a few miles, straight down the road.
  • buffalonickelbuffalonickel Member Posts: 113
    The original question seemed to tip the scales. My question came to mind when I was reading the owner's manual for my new '03 about driving the Taco in 4WD for 10 miles a month to keep all the parts lubbed up. I remembered a Toyota service manager telling me to avoid putting my transfer case in 4WD on dry pavement and it just seemed to be a good question.

    Thanks for the input.

    B
  • wwestwwest Member Posts: 10,706
    Was a good question and remains so. I stand by my earlier statement, 10 miles a month on dry pavement with a locked center Diff't means you accrue 480 miles of extreme drivetrain wear in just 48 months. I certainly wouldn't want to be the unlucky person who purchases your (WELL) used SUV after that.

    And are you really sure that your owners manual doesn't refer to putting your "taco" into AWD (sometimes referred to as "full-time 4WD") once a month? It seems to me that would serve the need for lubbing up all the gears just as well as putting it in (part-time) 4WD.

    Asked the question although I have no idea if the taco has an AWD mode.
  • intmed99intmed99 Member Posts: 485
    The Tacoma does NOT have a AWD mode. It is a simple, part-time 4wd system...2wd, 4HI (center lock), and 4LO (center lock). You canNOT use the Tacoma's 4wd system regularly on dry land. HOWEVER, like the manual says, you need to put into 4HI about 10 miles/month. If you're not the off-roading type, then you need to drive in a straight line 10 miles a month.
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