Page 1 of 2 12 LastLast
Results 1 to 10 of 15

Thread: 4l60e TCC Lockup unlocking at 0% throttle

  1. #1
    Junior Member
    Join Date
    Jan 2015
    Posts
    25

    Default 4l60e TCC Lockup unlocking at 0% throttle

    I'm having this issue where my TCC unlocks at 0% throttle at 65 km/h. When logging, "TCC Off due to Minimum throttle" value goes to yes. I can't for the life of me figure out why since I have TCC release set to 50 km/ H or 100% throttle. If I'm cruising at 100km/h and release the throttle, TCC will remain in coast mode up until 65 km/h then release.

    This is annoying in the city because if I'm driving at 62km/h, the engine revs a little then locks right away at light throttle because it should be locked at say 50 km/h

    What all controls TCC lock and unlock? What am I missing?

  2. #2
    Lifetime Member
    Join Date
    Mar 2006
    Posts
    4,880

    Default

    What vehicle and PCM/TCM? It is a separate parameter from the TCC lock/unlock tables. I believe all truck OS' unlock at 0% TPS while car OS' stay locked at 0% TPS. Depending on PCM/TCM, the parameters may/may not be available.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

  3. #3
    Junior Member
    Join Date
    Jan 2015
    Posts
    25

    Default

    1998 Chevy truck and I am using a 411 pcm with a 4l60e transmission. What I don't understand is the TCC stays locked when off the throttle at any speed over 65 km/h. If I'm cruising at 70km/h and TPS goes to 0, TCC stays locked. If TCC is locked and going 65 km/h and TPS goes to 0, TCC unlocks.

    I've read a few people have made the TCC stay locked on hp tuners forum but I can't figure out how to do so on EFI live.
    Last edited by Mr98z71; November 22nd, 2020 at 12:26 PM.

  4. #4
    Lifetime Member
    Join Date
    Mar 2006
    Posts
    4,880

    Default

    Post your tune and I'll take a look. If it's staying locked above a certain speed, it's likely due to the TCC lockup table settings. The "hurdle" is getting a truck OS to stay locked at all under 0% TPS, in factory form they unlock regardless of speed.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

  5. #5

  6. #6
    Junior Member
    Join Date
    Jan 2015
    Posts
    25

    Default

    I hope that worked

  7. #7
    Lifetime Member
    Join Date
    Mar 2006
    Posts
    4,880

    Default

    Can you post a log of it happening as well? I see your TCC lock/unlock appears to be set correctly based on your description. Do you have different tires or gears and have you accounted for them in the tune? Thinking if your speedo is off due to larger/smaller tires or gears, there may be a correction factor needed.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

  8. #8
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,010

    Default

    Truck LS1B 4L60E/4L80E calibration: TCC is unlocked at zero TP regardless of TCC release curve.

    F-car/Y-Car LS1B 4L60E calibration: TCC stays locked at zero TP unless VSS drops below TCC release curve.
    Last edited by joecar; December 11th, 2020 at 02:35 AM.

  9. #9
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,010

    Default

    You may have to check tbat the TCC apply/release tables do not cross.

    (same with VSS/TP upshift/downshift tables, make sure they're not crossed).

  10. #10
    Junior Member
    Join Date
    Jun 2011
    Posts
    45

    Default

    Yeah this is an option efilive has refused to include in their definitions even though HP tuners has had it for the better part of a decade.

Page 1 of 2 12 LastLast

Similar Threads

  1. T43 Acadia Transmission Tuning for TCC locking and Unlocking
    By ZigBlazer in forum 6 speed/8 speed RWD/FWD Transmission Tuning (incl T43, T76, T87)
    Replies: 12
    Last Post: April 7th, 2020, 04:57 AM
  2. 4l60e slipping? or TC locking and unlocking
    By blindawg in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 1
    Last Post: December 24th, 2014, 05:20 PM
  3. 4l60e Problem with TCC lockup in 4th below 39mph with a vacuum modulated valve body
    By sac811 in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 0
    Last Post: April 9th, 2013, 02:54 PM
  4. 3rd Gear TCC locking/unlocking issue
    By 1BadAction in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 19
    Last Post: August 31st, 2012, 02:41 AM
  5. TCC lockup again
    By DURAtotheMAX in forum Allison 5 & 6 Speed
    Replies: 17
    Last Post: April 23rd, 2011, 01:21 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •