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A-TRAC/TRAC/AUTO LSD Explained (Easy to understand, I hope!)

Discussion in 'Technical Chat' started by David K, Jan 19, 2010.

  1. Mar 7, 2010 at 10:08 AM
    #21
    David K

    David K [OP] Well-Known Member

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  2. Mar 23, 2010 at 6:48 PM
    #22
    SOSHeloPilot

    SOSHeloPilot Well-Known Member

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    Finally, got my "first 4x4" in a Tacoma. Barcelona Red w/ JBL & Entune - Then traded it in on a Ridgeline.
    .

    Super write ups and thanks for your time to write and post all this info.

    You could make some good money writing military equipment manuals.

    Thanks again for doing these write ups ...

    .
     
  3. Mar 24, 2010 at 8:31 AM
    #23
    David K

    David K [OP] Well-Known Member

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    Thank you! Also, I could use some good money... ! Have a great day!
     
  4. Apr 21, 2010 at 10:38 AM
    #24
    DEEVON911

    DEEVON911 Semi-pro

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    Thank you very much for the great write up! Everyone! I was truly confused when I looked at those buttons and tried to read what they where in the manual. Don't off-road myself alot but deal with a decent amount of snow here and there. This info will really help me deal with the deep stuff. Thanks again for really explaining it!
     
  5. Apr 21, 2010 at 3:28 PM
    #25
    David K

    David K [OP] Well-Known Member

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    Glad you found it helpful Dave!

    I came to this forum seeking help when I got my 2010 Tacoma last December... It has been great fun reading so many explanations for it... and then trying to combine the good stuff into a short, easy to use guide... Actually using the various drive modes in real off road situations is where the beauty of TRACTION and ACTIVE TRACTION control, coupled with the four wheel drive is where they prove themselves. It may help that I have had two earlier 4x4 Tacomas (1st and 2nd Generation) to compare it to, as well.

    Let us know how well you find the new systems do in your situation!
    David K:)
     
  6. Apr 26, 2010 at 7:56 PM
    #26
    LawP

    LawP Well-Known Member

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    Thank you, this is exactly what I needed to read. Great write up.
     
  7. Apr 27, 2010 at 7:07 AM
    #27
    David K

    David K [OP] Well-Known Member

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    My pleasure! I know that when I want an answer to a question... I want it NOW!!

    The drive modes shouldn't be a secret...

    1) 2WD: VSC and TRAC active, engine regulated ('Limited Slip Lite').
    2) 2WD: 'AUTO LSD' ('TRAC OFF MODE'). No engine regulation for 'strong' limited slip.
    3) 2WD: 'VSC OFF MODE' (TRAC is off for 'open differential').
    4) 4WD-Hi: VSC and TRAC active. No engine regulation for 'strong' limited slip.
    5) 4WD-Hi: 'VSC OFF MODE' (TRAC is off for 'open differentials').
    6) 4WD-Lo: VSC and TRAC are both off in L4 ('open differentials').
    7) 4WD-Lo: 'A-TRAC' on gives a 'locker-like, super strong' limited slip, front and rear.
    8) 4WD-Lo: Rear Differential Locked and open front differential (A-TRAC off).
    9) 4WD-Lo: RR DIFF LOCK + A-TRAC on, 3 MPH limit.
     
  8. Apr 28, 2010 at 10:51 AM
    #28
    David K

    David K [OP] Well-Known Member

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    I have fielded some questions about the 9 drive modes... Some are concerned that they 'need' to be using them all and it becomes complicated.

    Yes, it does... but the good news is that these are only options you have and realistically you won't need to use or know all of them.

    In fact, you likely only need to know that the standard mode in H2 and H4 will be perfect for perhaps all your High Range needs.

    In L4, I recommend that you push the A-TRAC switch once... and automatically your truck will be in A-TRAC every time you go into L4 which is the maximum traction choice without limitations to use or steering ability.

    So, of the 9 drive mode options... these are the three you will be using the majority, if not all the time:

    1) 2WD: VSC and TRAC active, engine regulated ('Limited Slip Lite').

    4) 4WD-Hi: VSC and TRAC active. No engine regulation for 'strong' limited slip.

    7) 4WD-Lo: 'A-TRAC' on gives a 'locker-like, super strong' limited slip, front and rear.
     
  9. May 2, 2010 at 9:19 PM
    #29
    NAYo2002

    NAYo2002 Well-Known Member

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    Ha ha that guy has a handicap plate... he doesn't look very handicap to me.
     
  10. May 3, 2010 at 4:41 AM
    #30
    kris77

    kris77 Born in the Backwoods

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    So, Im guessing since i have an 08....Im outta luck on this.

    Knew i should have waited for an 09
     
  11. May 3, 2010 at 9:14 AM
    #31
    David K

    David K [OP] Well-Known Member

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    Trade up to a '10!
     
  12. May 6, 2010 at 8:52 AM
    #32
    TacomaFanNC

    TacomaFanNC Active Member

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    What mode would you suggest for driving on the beach in fairly deep, loose, rutted sand? Also, what's the best tire pressure for sand?

    Thanks!
     
  13. May 6, 2010 at 9:29 AM
    #33
    David K

    David K [OP] Well-Known Member

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    From personal experience, in Baja... H4, normal (TRAC ON) mode. Deflating no may no longer be needed with TRAC ('09 or newer OR 4WDs).

    If the ruts in the beach slow you down too much and there is an issue with moving, stop and shift into Neutral then L4 with A-TRAC on... continue... You can always deflate the tires if you need better floatation.

    I go to a beach where the sand can swallow any 4X4 that doesn't deflate their tires, and for the first time didn't need to with the new Tacoma using TRAC.

    For fun, I turned off the TRAC (VSC OFF mode) to make my 2010 the same as my 2005 Tacoma (open differentials) and could only drive a few feet in 4WD before getting stuck (tires at 32 psi)! I went into L4 with A-TRAC,and drove OUT of the stuck, without letting any air out of the tires or digging sand away from the front of the burried tires... it was awesome.

    Once out, I went back into H4 (normal, TRAC on) and never got stuck again.

    TRAC in H4 is Limited slip that puts torque to all 4 tires and A-TRAC is even stronger, like lockers front and rear for really tough conditions.

    Here I am wheeling in H4 on the beach south of San Felipe, at 32 psi, the first time in Baja with my new truck:

    [​IMG]

    [​IMG]

    [​IMG]

    My 2005 Tacoma would have sunk in in about 100 feet onto that sand requiring me to deflate the tires to 15 psi. There is an obvious superior advantage to the TRAC and A-TRAC system!
     
  14. May 11, 2010 at 6:40 PM
    #34
    ppeter

    ppeter Nerdfighter

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    It's been 2 months since I got a 2010 DC 4X4 auto TRD off road. I've tried several times to figure out DAC and A-trac and I think that I must be doing something wrong. Or I have a problem. First the DAC light in the dash blinks...but never goes to solid. I've tried every thing I can think of 2H 4H 4L in every gear and every speed and nothing ever happens. Besides the light blinking LOL. I fall off steep hills and paved grades with no restriction whatsoever. As a side note uphill assist works just fine.
    Also I have tried to turn A-trac on in 4L, Park through low gear, but it will only work when the rear diff lock is engaged. Without the diff lock the A-trac button doesn't do anything (open differentials). On David K's signature "7) 4WD-Lo: 'A-TRAC' on gives a 'locker-like, super strong' limited slip, front and rear."
    What step am I missing...or...should I contact the dealer? Thank's! You guys are so helpful :)
     
  15. May 12, 2010 at 8:49 AM
    #35
    David K

    David K [OP] Well-Known Member

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    Okay, let's see what is going on here...

    1) A-TRAC and the Downhill Assist both only work in L4 (Low Range 4WD).

    2) To get into L4, stop the truck... and put tranny into NEUTRAL (NOT PARK!)!

    3) Rotate dial while pushing in to L4 from H4 or H2... and see Low Range indicator light go on, solid.

    4) Push A-TRAC switch once. A-TRAC will now come on every time you go into L4 (as it should). Only if you want open differentials in L4 would you ever push that switch again.

    When you are about to drop down a steep grade and want to use the Downhill Assist, just push that switch and take you foot off the brake! You will trickle down the grade without locking tires and causing a skid that couild pitch your truck sideways with potential for rollovers.

    When you are down crawling uo and down grades, rotate the transfer case dial from L4 to H4. Next time you go into L4, the A-TRAC will come on automatically.

    Have Fun!

    PS, what is 'Uphill Assist'?
     
  16. May 12, 2010 at 9:02 AM
    #36
    Shack

    Shack Well-Known Member

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    I think he is referring to hill start assist.:confused:
     
  17. May 12, 2010 at 9:12 AM
    #37
    David K

    David K [OP] Well-Known Member

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    He said he has an automatic... ??? I don't have a Hill Start Assist on my Automatic...
     
  18. May 12, 2010 at 9:27 AM
    #38
    ppeter

    ppeter Nerdfighter

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    Yeah sorry, it's hill start assist. There's no button to push, you just press on the brake hard when your stoped on a grade and the brakes hold you for a few seconds while you get on the throttle.
    Unfortunately I do think there's a problem. Both systems are not working properly (as described). Thanks a bunch for your response! I'll take it to the dealer when I can.
     
  19. May 14, 2010 at 12:33 AM
    #39
    06rubi

    06rubi Well-Known Member

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    Great write up! All the dealer told is was to push the VSC in L4 to turn off the air-bags! The first offroad excursion we took it on we went through some deep whoops and the A-TRAC pulled us over them. It was not as smooth as my Jeep with F/R lockers since the brakes are pulsating. I wonder if the hill assist is part of the system? The truck is a 6 speed, if I have time tomorrow I'll go to the hills and play around and see what I can figure out. If we have it'll be great! Really come in handy when you are off camber on a rock and stop. On my Jeep I installed a hand throttle for those situations, but this could be safer and easier.
     
  20. May 14, 2010 at 6:30 AM
    #40
    David K

    David K [OP] Well-Known Member

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    Wow, the dealer's (not just yours) lack of knowledge is pretty sad!

    Keep on four wheeling and report back!
     
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