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Downhill control or transmission?

Discussion in '5th Gen 4Runners (2010+)' started by Riding Dirty, Feb 1, 2018.

  1. Feb 1, 2018 at 8:04 PM
    #1
    Riding Dirty

    Riding Dirty [OP] Sinner; saved by grace

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    Is plasti-dip a mod?!
    I have a certain long grade downhill stretch of road I take daily. It is at a stoplight, so most of the time you must stop and wait your turn, then turn and travel down it. But when you do, the transmission up shifts to 3 or 4, but won’t upshift further even when accelerating, running the rpms to about 2500-3000. It’s a steep, but drawn out down hill section, and once I get to the bottom of it and the road becomes level again, the tranny will upshift and ride like usual. This is the only place I have this issue.
    So, is this a possible torque converter or tranny issue or is this the downhill grade assist?
    Or possibly just the grade logic working on a downhill grade and normal?
     
    Last edited: Feb 1, 2018
  2. Feb 2, 2018 at 6:39 AM
    #2
    COexplorer

    COexplorer New Member

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    I live at the top of a large hill, then travel down a canyon about 2000 ft every morning. Mine in constantly downshifting whenever I touch the brakes, then running at higher RPM's than I would like, then upshifting. It gives it a very jerky feeling, especially coming into turns and can be downright scary when it is icy. It is one of the few things I dislike about the 4Runner. I am hoping that Toyota will come out with a reflash to address this.
     
  3. Feb 3, 2018 at 8:36 AM
    #3
    j cat

    j cat New Member

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    so going down a steep grade you lightly touch the brake pedal and the tranny down shifts... foot off pedal back to OD...

    I will have to check that out ..
     
  4. Feb 3, 2018 at 6:13 PM
    #4
    Riding Dirty

    Riding Dirty [OP] Sinner; saved by grace

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    Is plasti-dip a mod?!
    Yes, I’ve noticed the engine braking when going downhill and touching brakes. Not an issue, as that’s common in lots of new vehicles. From what I’ve read, this staying in a lower gear like I described above appears to be part of the grade logic programming just wanted to see if others are experiencing it and normal behavior. It just struck me odd, as it sounds and feels weird that the engine revs out to 3k before upshifting.
     
  5. Feb 4, 2018 at 5:44 AM
    #5
    j cat

    j cat New Member

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    I did check this out yesterday not a steep grade as there are not many in my area now. I was doing 50MPH put foot on brake pedal lightly, no down shift going down a grade rpm did not rise.

    possible a 2017 PCM change.
     
  6. Feb 4, 2018 at 10:22 AM
    #6
    Riding Dirty

    Riding Dirty [OP] Sinner; saved by grace

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    Is plasti-dip a mod?!
    Hmmmm, interesting. It may well be a pcm change. I’ve also searched and found a few threads in t4r.org with this, and it seems like it’s a normal thing. Just odd to me I guess. I was hoping others had it too.
     
  7. Feb 4, 2018 at 12:39 PM
    #7
    j cat

    j cat New Member

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    the new GM trucks have this down shift going down steep grades but I never had them say foot on brake.. so going down steep grade the PCM puts it in a lower gear to keep the speed constant ..
    they also do not like it so use a diablo tuner to tune it out ...

    no tuners for toyota .. gm/dodge/ford yes..
     
  8. Feb 6, 2018 at 2:41 PM
    #8
    TN_TRAIL

    TN_TRAIL New Member

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    oh the list....!
    You guys bring up an interesting point that I had not really considered with mine. I have been in the habit for years of using the engine as a brake, but have noticed a few times on one stretch of daily road that mine will exhibit similar behaviour as well. Have not put all the variables yet to test, but it also seems to be tied to speed as well. Will have to do a test, and report back.
     
    Riding Dirty [OP] and j cat like this.

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