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AutoLSD is it LSD??

Discussion in '2nd Gen. Tacomas (2005-2015)' started by Taco Guy11, Oct 21, 2011.

  1. Oct 21, 2011 at 10:13 AM
    #1
    Taco Guy11

    Taco Guy11 [OP] Well-Known Member

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    Ok im new to the tacoma thing i have been looking trough threads about autoLSD and that its electronically controlled with the brakes ok. I i have a several chevys and a ford the LSD in them was mechanical and was in the rearend when the tired slipped it used springs and clutches to make the other tire spin to not being pegged legged. So does my 2011 dbcb trd sport have just the electronic controlled AutoLSD or does it have a mechanical system in the rearend too? Thanks in advanced for any help and im sorry this has probably been asked many times.
     
  2. Oct 21, 2011 at 10:18 AM
    #2
    David K

    David K Well-Known Member

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    ALL Tacomas since 2009 have electronic/ brake controlled limited slip. A mechanical limited slip (only in 2005-2008 Sport TRDs) used clutches that slow one side... same principle, slowing the low traction tire so power transfers to the traction tire.

    You have two levels of limited slip in 2WD:

    TRAC (normal mode): brakes and engine output regulation to reduce spinning of the low traction tire.
    AUTO LSD (press VSC button quickly): brakes only, no engine regulation. Use if you get stuck.
     
  3. Oct 21, 2011 at 10:18 AM
    #3
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

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    FlimFlubberJAM
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    4.10 gears, sliders, and lots of buttons.
    You have no sig.....
     
  4. Oct 21, 2011 at 10:19 AM
    #4
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

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    The mechanical LS Diff was an option on all SR5 Pre runners also. Some SR5 4x4's have them too.
     
  5. Oct 21, 2011 at 10:23 AM
    #5
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

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    Im not doing anything. Im thinkin, that when you use your phone, you have the "include signature" turned Off.
     
  6. Oct 21, 2011 at 10:24 AM
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    David K

    David K Well-Known Member

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    Thanks, I didn't know that you could have a limited slip and a locker (PreRunner) together?
     
  7. Oct 21, 2011 at 10:25 AM
    #7
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

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    Please notice I had said the "LS DIff" was an option on the "SR5" package trucks. If you have an TRD Off Road, then you can only have the locker.
     
  8. Oct 21, 2011 at 10:26 AM
    #8
    David K

    David K Well-Known Member

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    Thanks.
    How do clutches speed up anything... I would thing that more engine torque would be the only way to do that?
     
  9. Oct 21, 2011 at 10:27 AM
    #9
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

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    It can also "slow" the faster wheel, as it tries to spin both tires at the same velocity.
     
  10. Oct 21, 2011 at 10:29 AM
    #10
    David K

    David K Well-Known Member

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    I saw 'PreRunner' and thought of TRD Off Road 2WD... Are there PreRunners that don't have the rear locker? I am not keen on the 2WD Tacomas, sorry!
     
  11. Oct 21, 2011 at 10:30 AM
    #11
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

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    No different than the 4x4's. Yes, there are Prerunners that dont have the locker. Some are open, some have an LS Diff......The Prerunner is the same platform as the 4x4, but without the front drive components.
     
  12. Oct 21, 2011 at 10:37 AM
    #12
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

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    I know.....and perhaps Im going a bit too deep in my statement. What Im saying is, torque is taken from the faster spinning tire and transfered to the slower one. This action in fact creates a little more drag on the faster tire, and "can" slow it down. On my Dodge, when doing a Donut, or some other antic, I could get smoke off the inside tire, and as the LS engauged, it would slow it down to match the speed of the other tire......I guess it all depends on static weight loading, and such.....
     
  13. Oct 21, 2011 at 12:13 PM
    #13
    monster38

    monster38 Member

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    Christian: In a limited traction situation where one wheel remains stationary and the other begins slipping, the spinning wheel will spin faster than the ring gear. In fact, if the stationary wheel is completely stopped, the spinning wheel will spin precisely twice as fast as the ring gear. There are some pictures on wikipedia that illustrate this very nicely.

    A mechanical LSD acts to lock one of the two driveshafts to the differential gear carrier (which is locked to the ring gear). This will cause the slipping wheel to slow down and the stopped wheel to speed up. If the clutch is on the stopped driveshaft, you could say that it acts to speed up that shaft. If the clutch is on the spinning driveshaft, you could say that it acts to slow down that shaft. Through the planet gear, it does the opposite to the other shaft.

    AutoLSD can be better than mechanical LSD.
    For one, it can actually be DISABLED.
    Second, and probably more importantly, autoLSD can operate on the FRONT. Not just the back. If you've driven pickups before (as you obviously have), then you're quite aware that 1 front wheel gives you more traction than TWO back wheels, so just imagine how much more traction you get from laying it down through ALL FOUR.
     
  14. Oct 21, 2011 at 1:04 PM
    #14
    monster38

    monster38 Member

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    No. If you put your transmission in park (e-brake off) and lift the back of your truck on a car jack under the differential, you can spin one of the wheels by hand and observe that the other wheel turns in the opposite direction. You will recognize that since the transmission is in park, the ring gear must be stationary while you're doing this. Obviously, neither shaft can be locked to the ring gear, or it wouldn't be moving.
     
  15. Oct 21, 2011 at 2:29 PM
    #15
    David K

    David K Well-Known Member

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    Great information, thank you. Just to help those who are confused by Toyotas naming... AUTO LSD is only a 2WD mode, but the same process is in 4WD-HIGH but is called TRAC there... limited slip without engine output regulation.

    [​IMG]
    Under 30 mph AUTO LSD has no VSC, over 29 mph the VSC is active.

    In 2WD, TRAC has engine output regulation and AUTO LSD does not.

    As monster38 says, you can de-activate TRAC and AUTO LSD by stopping the truck and holding in the VSC switch (button) for a few seconds until the light comes on...

    [​IMG]

    [​IMG]


    I did a thread on traction levels... and as monster38 says, two back tires is better than one (limited slip or rear locker), but one front and one rear tire is better than just the rear powered (standard 4WD, open diffs.)

    *Next level up is limited slip on the front and rear (TRAC in H4)...

    *Next or tied is the rear locked and an open front diff. (pre-'09 Off Road 4WDs)

    *Next (or the top) level is A-TRAC or aftermarket front + rear lockers. (those with front lockers will say lockers are superior to A-TRAC... an opinion, as A-TRAC is very close and is included with our trucks, but A-TRAC wins at allowing steering since it doesn't bind the differential)
     
  16. Jan 11, 2012 at 5:30 PM
    #16
    frog13

    frog13 Well-Known Member

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    So if one doesn't off road....do I really need 4wd for "just" snow and ice. I had a 1992 Ford F-150 2wd that was horrible in the snow....I never want to repeat that experience!.I'm aware that tire's make the difference...it did not on the F-150 I had.
     
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