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Transmission hard/weird downshift issue

Discussion in '2nd Gen Tundras (2007-2013)' started by cfe4130, Dec 3, 2019.

  1. Dec 3, 2019 at 11:24 AM
    #1
    cfe4130

    cfe4130 [OP] New Member

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    I have a 2012 4.6 and I just took it from Louisiana to Tulsa, OK over the holidays. This was the first road trip since purchasing it in November. On the way home I started to notice a weird downshift going up hills. It was similar to driving on the cut outs on the interstate that let you know you are too far to the left or right. Sort of like a “braaap” vibration feeling.
    While driving today I noticed the same feeling when it shifted around 40-50 mph driving on local streets. Do I just need a fluid change or could this be something worse?
     
    Rica25 likes this.
  2. Dec 6, 2019 at 9:33 AM
    #2
    NWExplorer

    NWExplorer this guy

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    Could be worn gears slipping in the rear diff or maybe transfer case? Seems to only happen under load. Do a fluid change on your rear diff and look for metal debris. Move to transfer case fluid next. Affordable approach and the fluids probably need changed anyway unless you have records of the maintenance.
     
  3. Dec 6, 2019 at 10:30 PM
    #3
    Scuba

    Scuba Sober member

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    I would definitely start by replacing the fluid in the transmission with a simple drain and fill. Document what the old stuff looks like. If it's dark black with specs of metal then your transmission or torque converter may be on the way out.
    How many miles on the truck? Do you have any maintenance records?
     
  4. Dec 10, 2019 at 12:27 PM
    #4
    cfe4130

    cfe4130 [OP] New Member

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    I did the rear diff fluid change last night, but I haven't driven it yet. The history report lists where service was done. I plan to call that dealership to obtain the records. It has 125k.
     
  5. Feb 14, 2021 at 10:20 AM
    #5
    cfe4130

    cfe4130 [OP] New Member

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    I never did update this thread, but after I did a drain and fill of the transmission fluid, the issue did not return. Fast forward to a little over a year later and 20k more miles, its back but in a different way. Now I'll get the feeling like I'm driving over a rumble strip in the road which occurs randomly between 30-40mph. A few times when this has occurred, I've moved the shifter into shift mode and the vibration stops. Also, it feels like it downshifts into 4th gear when put into shift mode. So should I do another drain and fill? I used Toyota AFT last time. Should I use a synthetic ATF this time?
     
  6. Jul 10, 2021 at 11:19 AM
    #6
    Jmunoz1977

    Jmunoz1977 New Member

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    This issue my friend is most likely torque converter. The fluid change most likely helped temporarily but the inevitable tc issue would reoccur and most likely worse. Some have had success with multiple drain and fills. Others didn’t and replaced the TC without further issues. Good luck
     
  7. Jul 10, 2021 at 8:41 PM
    #7
    blackdemon_tt

    blackdemon_tt Battery Slayer

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    Man, it appears as I just encountered this today. Excessive vibration in the cab at 30mph.. then it was gone.. TC going is good to know...


    Edit: then again it's Kali... may just be the shitty roads..
     
  8. Nov 5, 2021 at 7:26 PM
    #8
    Islander

    Islander New Member

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    Had the same problem last April. Transmission shop wanted to replace TC. Expensive! Had the trans fluid changed (flushed) at Toyota dealership. No change for 800 Km then it was like having a new transmission! That was 7000 km ago and it still feels perfect.
     

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