1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Vehicle shut off while rolling back in L4/Drive

Discussion in '3rd Gen. Tacomas (2016-2023)' started by mandog, Mar 21, 2021.

  1. Mar 21, 2021 at 12:00 PM
    #1
    mandog

    mandog [OP] Lesser-Known Member

    Joined:
    Oct 7, 2019
    Member:
    #307297
    Messages:
    459
    Race City, USA
    Vehicle:
    2017 4WD Off-Road Quicksand Overland
    Anyone know what could have caused this? It's an automatic 4WD TRD OR (2017)

    I wasn't in the driver seat, but was spotting while doing a slick rock climb in Sedona.

    Driver was easing up an aggressive slope in L4 and rear tires began to spin. I said to let it roll back and come to passenger, but they had ultimately lost steering power and couldn't turn. It was kinda noisy there and so when I walked over to the vehicle, it had shut itself off.

    No start/stop button was pressed and truck was still in Drive/L4. Is this a protective measure for the transfer case? Obviously they should have just come to neutral, but my guess is, there must be some threshold for rolling back in drive to where it safeguards and shuts off.

    The truck wheeled fine afterwards and completed the hill on 2nd attempt, but I'd like to know more about what happened for future wheeling expeditions. I've read forums on rolling back in drive, but nothing about an engine shutoff because of it. Thanks for your input!


    For reference of the climb, here's a video I found..

     
  2. Mar 21, 2021 at 1:30 PM
    #2
    ShimStack

    ShimStack Well-Known Member

    Joined:
    Mar 11, 2012
    Member:
    #74701
    Messages:
    1,652
    Gender:
    Male
    First Name:
    Ben
    NC
    Vehicle:
    '91 Truggy, '98 Project, '16 DC OR M/T Locked F/R
    Automatics can be stalled. Rotating the transmission backwards against the torque converter isn't the greatest of situations. Especially in LO.
     
  3. Mar 21, 2021 at 1:50 PM
    #3
    mandog

    mandog [OP] Lesser-Known Member

    Joined:
    Oct 7, 2019
    Member:
    #307297
    Messages:
    459
    Race City, USA
    Vehicle:
    2017 4WD Off-Road Quicksand Overland
    It definitely seemed like a stall. Okay, thanks for answering that. Obviously I would not try to replicate that situation. Cheers
     
  4. Mar 21, 2021 at 1:54 PM
    #4
    ShimStack

    ShimStack Well-Known Member

    Joined:
    Mar 11, 2012
    Member:
    #74701
    Messages:
    1,652
    Gender:
    Male
    First Name:
    Ben
    NC
    Vehicle:
    '91 Truggy, '98 Project, '16 DC OR M/T Locked F/R
    Remember, in low, rolling back at a "normal" speed equates to 2.57x over drive speed at the transmission compared to "normal". This is extra load in the torque converter and thus at the engine which is just idling.
     
  5. Mar 21, 2021 at 1:55 PM
    #5
    EatSleepTacos

    EatSleepTacos Well-Known Member

    Joined:
    Mar 24, 2015
    Member:
    #151688
    Messages:
    59,836
    Gender:
    Male
    First Name:
    Randy
    West Valley, AZ
    Vehicle:
    2017 4Runner
    Yep I’ve seen a third gen auto stall a couple times in a similar situation. I wouldn’t worry too much about it.
     
    mandog[OP] likes this.
  6. Mar 21, 2021 at 2:02 PM
    #6
    mandog

    mandog [OP] Lesser-Known Member

    Joined:
    Oct 7, 2019
    Member:
    #307297
    Messages:
    459
    Race City, USA
    Vehicle:
    2017 4WD Off-Road Quicksand Overland
    This is maths. And for that reason...
    sharktank-2.jpg

    Just kidding. It's more of an answer than I could have asked for, so thanks for breaking it down. Knowing what's behind the mechanics helps me to make smarter decisions in the moment.
     

Products Discussed in

To Top