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Toyota 4WD systems explained

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Comments

  • wwestwwest Posts: 10,706
    Sorry, I wasn't even aware that earlier AWD Highlanders (or even that there were earlier AWD HLs) used the VC, and right now I'm drawing a blank as to when or where I might have said something in conflict with that.

    If you don't mind helping at a slightly deeper level I'll be glad to go back and correct my mistake insofar as that might now still remain possible.

    Given the RXes transition away from the VC starting in '04 this does not surprise me in that respect.
  • 2toyotas2toyotas Posts: 104
    TRANSFER
    1. General
     The ’05 Sequoia uses the multi-mode VF4AM transfer.
     Along with the adoption of the VF4AM transfer, the transfer lever has been discontinued. Thus, in the
    4WD mode, the driver operates the 4Lo switch to switch between Lo and Hi.
     The VF4AM transfer is already in use on the ’04 4Runner with the 1GR-FE engine. For details on the basic
    construction and operation of the VF4AM transfer, see the ’03 4Runner NCF (Pub. No. NCF238U).

     Specifications 
    Model ’05 Sequoia ’04 Sequoia
    Engine Type 2UZ-FE 
    Transfer Type VF4AM VF3AM
    Drive Type Multi-mode
    (Part-time & Full time) 
    H2 1.000 
    Gear Ratio H/H4 1.000 
    L/L4 2.566 
    Reduction Gear Type Single Pinion Planetary 
    Center Differential Gear Type TORSEN LSD*2 Double Pinion Planetary
    Oil Capacity
    Liters (US qts, Imp.qts) 1.4 (1.5, 1.3) 1.2 (1.3, 1.1)
    Oil Viscosity SAE 75W-90 
    Oil Grade API GL-5 API GL-4 or GL-5
    Weight (Reference)*1 Kg (lb) 41.2 (90.8) 42.8 (94.4)
    *1: Weight shows the figure with the oil fully filled.
    *2: TORSEN is TOYODA-KOKI-TORSEN’s registered trademark

    This is 2005 sequoia showing the torsen, if you need more things from techinfo that you posted wrong let me know.
  • wwestwwest Posts: 10,706
    Yes, I have quoted this one, exactingly, myself, but my further point was that the very same 2007 documentation set (as also does the '08 and '09) indicates the MF2A continues to be used, just as it was/is in the the RX330.

    Do a "summary" search for MF2AV in '07, '08, and '09 and you will find only the '07 NCF you referenced. On the other hand search for MF2A in '07, '08, and '09 and you will find that all three years indicate the continued, continuing, use of the non-VC transfer.
  • wwestwwest Posts: 10,706
    Because hdfatboy was specifically addressing the '08 Sequoia I concentrated my research efforts on that model year. Can you tell me where or how I have managed to misquote the overall status or condition of the '05 Sequoia and I will attempt to correct the matter.

    Also just where or how do you obtain these particular quotes, I have searched and cannot find them.
  • 2toyotas2toyotas Posts: 104
    Yeah just New Car Features at Techinfo, and the LEXUS web site, which says VC center diff!!
    ARE YOU SERIOUS??
  • wwestwwest Posts: 10,706
    2toyoyas,

    I found the information on the '05 Sequoia at Techinfo.toyota.com and that brings my puzzlement level even higher.

    Yes, that reference shows that the '05 Sequoia uses the Torsen diff'l but it references the '03 4runner to find details. The '05 Sequoia credits "Toyoda-Koki-Torsen" as "Torsen" trademark owner. On the other hand the referenced '03 4runner information credits ZEXEL as owning the "Torsen" trademark.

    I'm pretty certain only teh ZEXEL ownership statement is correct.

    The '03 4runner documentation for the transfer and the Torsen unit is put forth in great detail. Even the Torsen unit itself is shown pictorially broken down to the basic components. Insofar as I could find there is no other 4runner nor Sequoia documentation that even identifies a transfer component as a Torsen Diff'l and sometimes the center diff'l is shown but not even identified as same.

    Which leads to the question...

    Did Toyota somehow get into legal trouble with ZEXEL?

    Is the Torsen diff'l actually used in later models but could not be legally identified as such. Or, as I have supposed, it is not used as all in systems with TC braking imposed AWD functionality..?
  • wwestwwest Posts: 10,706
    "ARE YOU SERIOUS?"

    About...??

    Specifically....?
  • wwestwwest Posts: 10,706
    2toyotas;

    What was the underlying question with your "ARE YOU SERIOUS" statement.

    And I should express my appreciation for your posts verifying that you have found the information at techinfo.toyota.com to be truthful,

    Were you satisfied with my responses about the items from techinfo...that you thought I have mis-represented??
  • harboharbo Posts: 136
    Where is the fuse for the power antenna?

    Thx ........
  • 2toyotas2toyotas Posts: 104
    Looks like the 2009 4Runner will get a locking rear differential, probably the same one that is in the FJ. It will only work in Low Range, and is engaged manually. i will keep everyone posted as soon as I am 100% certain.

    On a different note, I bought my wife a Land Rover LR3 in march, and took it to Rausch Creek Off Road Park on Sunday. It has an auto locking center and rear differential, the locking rear is an option, and most don't have it. Sunday was an event for the Land Rover dealership, so i was with all Land Rovers. We were in Low Range all day, and the LR3 was very impressive. The center and rear diffs lock and unlock automatically so you get maximum traction when needed, and also the ability to make tight turns very easy. The locking rear makes it easier than traction control, because you can just creep along, whereas traction control needs wheel slip to engage.
  • wwestwwest Posts: 10,706
    "We were in Low Range all day...'

    Useless bit of information, that.

    Unless you buy an $$$ LR3 exclusively for off-road use.
  • heyboerheyboer Posts: 6
    Greetings. Just got a 2004 V8. Have never gone offroad but will be near some dunes in Michigan next week and might give it a try. Owners manual vague about drives etc. so........When in a sand dune should it be 4hi or 4lo and what about the center diff?

    New question... from what I have read I will NEVER lock the diff when on pavement, even snow covered. If I'm in snow what speed is too fast for 4 low? I bought the 4runner to pull a boat. I use 4low on the ramp. I don't touch the diff. is this OK?

    Thanks in advance. I read almost every post here. Still confused LOL!
  • blackdog4blackdog4 Posts: 67
    Having driven on the sand a lot on the beaches of New England, the most important advice that I can give you is to be sure to deflate your tires to 15 psi before driving onto the sand. I have a 2002 Sequoia and just push the 4wd button. I have never had to lock the center differential or use low gear. You should also carry a tow cable and shovel. I have never had to use them for myself but have used them to help others who were stuck and digging deeper. Be sure you know how you are going to reinflate your tires after coming off of the sand.

    Many areas that allow access to their beaches have rules that are posted. Be careful of recently hatched shore birds. To prevent erosion of dunes usually they want you to stay on the trails.

    You will be entering a whole new world. Enjoy it. You should have no trouble with your having a 4 Runner.
  • harboharbo Posts: 136
    What's your experience with the (stupid) vsc that cuts back engine power just when you need it to stay on top of sand, soft dirt etc etc ??
  • nedzelnedzel Posts: 787
    Locking the center diff on the 4Runner disables VSC. When I take my 2003 4Runner on the beach, I air down to 15 psi, lock the center diff, and put it in low range. I've tried both low and high range on the beach, and it seems to take less throttle at the same speed in low range. YMMV.
  • harboharbo Posts: 136
    This is a RWD toyota Sequoia. The VSC cut engine power when it detects the slightest wheel slippage. Cut the power and you are now sinking in loose sand, snow, mud etc., just when you need the power to stay on top.

    HELP ....... thx in advance.
  • wwestwwest Posts: 10,706
    It's really the TC, Traction Control, mode, functionality, that acts to prevent wheelspin/slip arising from too much engine torque, not VSC.

    In any case you can quite easily disable both by unplugging the MAF/IAT module briefly with the engine idling. The result will be a CEL and by default a TC/VSC disable for the next few drive cycles.

    For their RWD and R/AWD vehicles Toyota has announced a NCF, New Car feature, in which activation of TC can be delayed in order to allow some level/period of driver controlled wheelspin/slip.
  • harboharbo Posts: 136
    Thx WWest. Got it.
    Were is the MAF/IAT modul?
    Are you saying it will stay disconnected for say, 4 or 6 starts? ... something like that. Chs
  • briegelbriegel Posts: 139
    I have a 2005 RX 330 AWD. What are the concerns with coasting downhill in NUETRAL at speeds ranging from 25-70 mph to save fuel? Potentially damaging to the transmission and/or the AWD system? Thanks!
  • wwestwwest Posts: 10,706
    The MAF/IAT module is mounted on top of the air intake just downstream, toward the engine, of the intake air filter.

    Unplug the connector with the engine idling, the engine will die, reconnect the MAF/IAT and restart the engine and be on your way. CEL will extinguish maybe as few as 3 restarts of the engine depending on the range of operations, city/hwy/etc, in the interim.

    ABS will continue to be enabled throughout.
  • briegelbriegel Posts: 139
    I posted this about a week ago...no response yet. Anyone have some thoughts?

    ********************************************************************************- **************

    I have a 2005 RX 330 AWD. What are the concerns with coasting downhill in NEUTRAL at speeds ranging from 25-70 mph to save fuel? Potentially damaging to the transmission and/or the AWD system? Thanks!
  • tidestertidester Posts: 10,110
    In addition to possibly being illegal, there are safety concerns. Besides, you're not really using all that much fuel driving downhill in gear anyway. The ECU senses the load on the engine and adjusts the flow of fuel accordingly.

    tidester, host
    SUVs and Smart Shopper
  • briegelbriegel Posts: 139
    Thanks for the reply. You are probably right, but the engine rpms do drop down to the idle range when coasting in neutral. However, I was told that the transmission fluid pump shuts off when in neutral so the fluid is not circulating through all the moving parts which could cause wear and damage...that is what I was mainly concerned about. Any thoughts on that?
  • tidestertidester Posts: 10,110
    If that's true then it would be a concern. Perhaps someone with knowledge of Toyota transmissions will chime in. Anyone?

    tidester, host
    SUVs and Smart Shopper
  • wwestwwest Posts: 10,706
    The gear type ATF pump is driven directly by the torque converter, if the engine is turning the pump is pumping...
  • I just bought a 4WD auto FJ which I'm loving so far. My salesman told me that I shouldn't use my 4WD for the first 5,000 miles--I've NEVER heard of this and need some other opinions... help! Thanks so much! (of course, I'm eager to take it out onto my property to do some hills, etc. to see how it does)
  • newdavidqnewdavidq Posts: 146
    The owners manual is always the best place to find answers. Your salesman is misinforming you (to put it nicely). I have a 4wd 4runner and the only restriction I noted when it was new last year was to not do any towing for the first 500 miles.
    Hope this helps.
    DQ
  • Last winter I lost traction & control coming down from the mountains in modestly icy conditions; speed was moderate; was surprised since I was in permanent (AWD) 4WD-High with VSD "on." Have Michelin Cross Terrain tires in very good condition. Was surprised to have lost complete control given the 4Runner's good reputation for these conditions. I have the V8 with full-time AWD (High/Low gear range switch selectable).

    What is the best 4WD configuration to be in in these conditions? (I thought about locking the differential but then you lose VSC - i.e. VSC turns off when you lock the differential, as I understand it)

    Thanks for any advice from other newer 4Runner drivers,

    Andrew
  • wwestwwest Posts: 10,706
    As a general rule you should NEVER use anything but RWD mode once underway at even moderately low forward speeds. This is especially true going mostly downhill.

    Remember that your traction coefficient with the roadbed does NOT change as a function of RWD/AWD/4WD/4X4 mode, only the efficiency with which you USE the available traction changes with drive configuration.

    4 wheel drive mode, like FWD or F/AWD, can be of great help getting up and going initially on a slippery or low traction surface, but can turn HAZARDOUS very quickly once underway. Again, most especially so, HAZARDOUS, on a slippery downhill drive.

    "I have the V8..."

    Even with the V6 you should never, NEVER, manually downshift the transmission for engine compression braking when on a questionable traction surface and in any "4" wheel drive mode. VSC does NOT have the ability to alleviate stability problems resulting from engine compression braking. Were I you I would even go to whatever extremes might be necessary (shift into neutral..??) to prevent even an automatic downshift in the conditions you describe.

    Oh, one other thing, in the conditions you describe the judious/careful/slight use of the rear implemented parking, e-brake, can oftentimes be of great help as an aid to keeping your speed low enough for conditions without threatening loss of control via "normal" front biased frictional braking.
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