Torque Converter engages disengages constantly on the freeway

Discussion in 'Transmissions' started by Big D, Mar 20, 2017.

  1. Big D

    Big D Atoadaso I f*kn Atoadaso

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    Never had this problem before, but if im on the freeway cruising around 60-65mph the torque converter will engage and disengage back and forth, trips me out. the only way to avoid this is haul ass at 75mph or cruise at 55..... I cruise at 55 for the most part.

    any Ideas? is it the torque converter? a solenoid? I have no idea as ive never dealt with this issue. I changed the transmission fluid last week to see if it would help, and it did not, other then I got fresh fluid pounded into her.

    1991 454 TBI Dually 4l80e 1 ton ac lifted on 33" tires.

    thanks in advance
     
  2. wingman

    wingman Newbie

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    Sounds like the problem I had with my 2001 2500HD with 6.0 and 4L80. In my case I cured it with a crank relearn, as the codes were showing random multiple misfires, causing the TCC to engage/disengage. May well not be the case with your set up, but it may just help. Good luck! Paul.
     
  3. Big D

    Big D Atoadaso I f*kn Atoadaso

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    I dont have a check engine light. im wondering/hoping if theres A solenoid issue that someone may be aware of.
     
  4. Stepside_fever95

    Stepside_fever95 I'm Awesome

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    First thing I'd do is change your brake switch, if it's bad it'll cause the cruise to work sometimes and the torque converter won't stay locked up. Replaced mine and it fixed my issue. Took like 5 minutes and was under 10 dollars.

    Sent from my SM-S920L using Tapatalk
     
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  5. Big D

    Big D Atoadaso I f*kn Atoadaso

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    http://www.thetruckstop.us/forum/threads/4l80e-transmission-problems.12979/

    Found this website and this article basically explains my issue, I was pretty sure it was the torque converter, this just re-assured me of it


    Article:

    No shift into OD under acceleration; OD will not hold under load and can hear or feel trans shift to OD when throttle is let off but slips into 3rd when throttle applied; sudden erratic lugging condition in lower gears when manually shifting: Bad news: this is going to involve a lot more time and money to fix this problem. The torque converter needs to be replaced, which requires between $300-$500 for a replacement, lockup, 4L80E converter. It is imperative that the replacement converter you choose is a lockup converter. The transmission will not hold in OD when there is a load on the drivetrain if the torque converter will not lock. The torque converter locks up (to make a solid, non-slip link between the engine and trans) in an effort to increase fuel efficiency and thereby reduce emissions on highway driving trips, when there is no heavy load on the vehicle (trailer or heavy weight in the bed). But, OD is a cruise gear, not a pulling gear, and as such to prevent the OD from burning out (from constant 3-OD up and downshifting and straining the OD with a 9,000 lb trailer) when towing something under load, the trans will force itself out of OD into 3rd when it detects that the converter is not locking up. The factory converter has an internal clutch that controls the lockup of the torque converter, and this clutch's torque capacity is minimal. Hence, if the clutch is going bad, just the weight of the truck and torque required to pull it will force the TCC to unlock the converter and a downshift to 3rd will occur. The lugging in lower gears (mostly first) is due to the converter locking up prematurely. Additionally, if left long enough, a look in the trans oil pan will reveal burnt fluid and black sediment. If there is black sediment in the pan before you notice drivability problems, it will soon be time to replace the converter. To replace the torque converter, you must either get the truck to a shop or have at least 2 jacks handy, one of which will be a transmission or motorcycle jack. An extra person to help out is a great asset, as the transmission weighs close to 200 lbs. This repair will take you about 6-9 hours to complete if you know what you're doing. Remember to fill the converter with as much fluid as you can before you install it. Don't worry about it all spilling out upon turning it on its side during installation; the fluid is slow going in and is just as slow coming out. At the very least, this is a good excuse to upgrade to a new, high performance converter with a little more stall speed (and a valid justification to the wife to spend $500 on another performance item!).
     
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  6. wheelman

    wheelman Newbie

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    TWO SHIFT SOLENOID,S UP IN THE TRANS.RIGHT THERE IN YOUR FACE.WHEN YOU TAKE THE PAN OFF.SOUNDS LIKE THE PROBLEM.TO ME.DO THE FILTER..I WAS TOLD THEY ARE LIKE 25.00 EACH..YOUTUBE HAS VIDEOS EASY TO CHANGE..WATCH A VIDEO.
     
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  7. Big D

    Big D Atoadaso I f*kn Atoadaso

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    I looked into the shift solenoids, it didnt seem to describe my issue. although I may swap them out since there relatively cheap on rock auto.
     
  8. C30454

    C30454 Newbie

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    You need to hook up a scan tool and see if the ECM is commanding the TCC on and off or not. If it is, then you need to look at all the parameters the ECM uses to determine lockup such as coolant temp, MAP, TPS, brake input, etc. Everything else is just someone guessing. With YOUR money.


    Tom
     
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  9. Big D

    Big D Atoadaso I f*kn Atoadaso

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  10. C30454

    C30454 Newbie

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    I've never used it, but based on the seller's description, yes.


    Tom
     

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