Howdy, Stranger!

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

Toyota 4WD systems explained



  • pschreckpschreck Posts: 524
    I was just going over the posts from the past couple of weeks. There seems to be a few missing. I wonder why.
  • pschreckpschreck Posts: 524
    I think you are correct in your prediction as to the demise of the old systems. Technology doesn't stand still does it?

    Thank you for answering my question about your Porsche. I can only imagine what it must be like to climb into something like that, let alone drive it.
  • wwestwwest Posts: 10,706
    Yes, and disc brake pads can be replaced in very short order by even a simple-minded DIY'r. Not like LSD clutch paks at all.
  • wwestwwest Posts: 10,706
    Software instead of LSD hardware....on the CHEAP?

    Cliffy1, you obviously haven't hired a really good "real time" programmer lately !!
  • pschreckpschreck Posts: 524
    I believe cliffy was being sarcastic toward an earlier post.

    You certainly are correct about brake pad replacement vs LSD replacement.
  • pschreckpschreck Posts: 524
    Land Rover doesn't use LSDs or VCs in their trucks? Holy cow! How do they get out of their driveways? ;-)

    Love my Sequoia!
  • brillmtbbrillmtb Posts: 543
    I will check my stack of mags for you to see if I still have it. I did some spring cleaning and hope it did not get tossed. I think the post after yours placed by the Sequoia owner also suggests some difficulty with the system under certain conditions like sand. I think Toyota will get the bugs out of the system and predict they will add in features that give the driver more control over the power distribution but we will see.

    Size: To tell you the truth I didnt think the Sequoia was so much bigger than the Montero that it would have made a difference to me. I end up pulling a trailer and may add a trunk on top but both situations would dictate that I jump to a full sized pickup with a crew cab to match or exceed those capacities. As such I am waiting for the new Ford diesel 6cyl with 400 ft lbs of torque next year. If they add a new truck, which is the rumor, that has a crew cab and 6ft bed this will handle both people and cargo better than an SUV. I am keeping the Monte because it does everything so well for its design. Forget about the roll over thing. I have talked to so many people who really use these SUV in high risk situations and roll overs is a concern for every SUV, not just the Montero. Also, the folks in Australia tell me they have had no reported problems and they even disconnect the sway bars for increased articulation.
  • pschreckpschreck Posts: 524
    Are you talking about the Tonka Ford with the hydraulic (sp) assist? That sure does look interesting.
  • pemarshpemarsh Posts: 68
    If the trans is in "drive", and I hit the 4wd the power to the front and back each 50% ??? Is the power to each tire 25%??
  • cliffy1cliffy1 Posts: 3,581
    In response to your message yesterday, Pschreck was correct in that I was being sarcastic. I appreciate your response to his question.
  • cliffy1cliffy1 Posts: 3,581
    The answer is a qualified "yes". It is qualified because it is only 25% per tire if traction conditions are equal at each tire and you are not turning a corner.
  • wwestwwest Posts: 10,706
    My friends often use me as the "straight" man in their jokes because I'm so slow to pick up on the fact that I'm being "ribbed".
  • brillmtbbrillmtb Posts: 543
    I dont know the meaning of "tonka" but it is my understanding that they did go to hydraulically actuated valves, dropping some 140 parts and from what I was told it should be almost as quite as a gas motor.

    If true, Ford is going to hit a home run with this and the V8 6.0l 600 ft lb torque diesel motor. There are plans to put it in the Expedition as well.
  • brillmtbbrillmtb Posts: 543
    It seems that my comment about updating the "Sequoia-like" VSC/Trac systems has already happened with the new Range Rover per the Speed Channel last night.

    Seems that the Range Rover folks noticed that there is a problem with this kind of system in certain situations where you need to maintain momentum, such as sand or mud, but where there is a risk of the motor powering down in an attempt to limit wheel spin.

    What they have done was to place a switch in the Range Rover to disable the VSC/Trac in these situations. This reverts the system back to something more like a standard 4wd lo/high range that will deliver power to the most number of tires all the time, slipping or not.

    This is what I think Toyota will realize in thier next generation systems. Until then, I think I still prefer driver controlled systems but I understand that not everyone is able to drive well on snow and the Toyota system should keep them out of trouble most of the time.
  • wwestwwest Posts: 10,706
    Nice thing about using software and "flash" non-volatile memory to implement functions, retrofitting new functionality is a piece of cake.
  • pschreckpschreck Posts: 524
    I referenced Tonka from Popular Science or Popular Mechanics. I'll see if I can find the magazine I saw it in.

    The Sequoia does have a VSC shutoff switch however I doubt that I'll be seeing mud deep enough to have to worry about it.

    I'm not sure how a part time 4WD system is any more controllable than a full time 4WD system.
  • steverstever YooperlandPosts: 39,957
    Ford Mighty F-350 Tonka

    Didn't you play with "Tonka Toys" when you were a kid, Brillmtb?

    SUVs, Vans and Aftermarket & Accessories Message Boards

    Need help navigating? - or send a private message by clicking on my name.

  • wwestwwest Posts: 10,706
    Controlable, I think, is not the issue.

    A part-time AWD/4WD system is called Part-time because it should NEVER be engaged on high traction surfaces. Part-time mode typically engages a SOLID connection between the front axle and the rear axle so they MUST rotate at exactly the same rate. When turning, front axles will inherently rotate at a rate different from the rear, but this is not a problem on low traction surfaces wherein the tire/roadbed "interface" is marginal and the slippage necessary to relieve the strain on the drivetrain can be accomplished there.

    Controlability only really comes into play if you have a Part-time system improperly engaged. In a tight, accelerating turn, for instance you might break your fingers, knuckles, or even parts of the drivetrain itsself.

    A full-time AWD/4WD system is one wherein the front axle and the rear axle remain coupled at all times but in not so solid a manner that some independent rotational rate cannot be accomodated.
  • brillmtbbrillmtb Posts: 543
    I also thought that AWD/Full Time would work better than part time mode until I actually started 4 wheeling in more hair raising circumstances. There is a difference. Its hard to explain but was very easy to see on my last visit to the fishing hole in the mud. I have imediate control of the front end, I mean within inches, in the part time mode. I think I may have gone swimming in the river if I had not. If you out in Oregon sometime I'll take you out and show you the difference.

    I dont think you would notice it on the street (ie snow) as much.

    When you turn off the VSC, what does the Sequoia now NOT do that it could before?
  • brillmtbbrillmtb Posts: 543
    I dont think I will need that Tonka truck anytime soon. I dont think I could find something large enough to tow with the 600 ft lb motor either.

    I am very interested in the v6 400 ft lb diesel that Ford is coming out with. There is a rumor that a slightly larger truck than the F150 will come out to accomodate a 6ft bed and crew cab. That would be perfect for me. Towing ability that surpases even most of the V8 gas motors with the mileage of a diesel. Way cool
Sign In or Register to comment.