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TC Lockup Switch

Discussion in 'The Garage' started by Hossbaby50, Oct 22, 2004.

  1. Hossbaby50

    Hossbaby50 3/4 ton status

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    I need to figure out how exactly to wire a torque converter lockup switch on my 700R4. I just want to put it on a manual toggle switch so I can kick the switch over when I am cruising on the highway so make sure the TC locks in OD.

    My TC only locks up randomly so I want to be able to override the system when cruising. Which 2 wires is it that I put on the toggle switch?

    I got a couple other questions too.

    Should the TC lockup when I am cruising in 3rd gear?
    How does the TC lockup work on an 85? Is it vacuum actuated or electrically activated? Thanks

    Harley
     
  2. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    I got this from Novaks site @ http://www.novak-adapt.com/knowledge/th700r4.htm

    [ QUOTE ]
    Lock-up converters in automatic transmissions give the advantage of direct engine lockup through the otherwise fluid-coupled transmission. This function works either by the ECM or a vacuum switch. Earlier versions without ECM use a vacuum switch connected to ported vacuum. The transmission receives the signal and applies fluid pressure to the clutches in the lock-up converter. The system switches off due to a signal from the brake pedal. If you run the transmission with the converter unlocked all the time it will run a little hotter. Keeping it cool is important. The advantage of this lock-up converter is increased fuel economy and decreased heat at cruising speeds.

    [/ QUOTE ]

    On my 83 its the vacuum switch next to the brake booster to turn mine off and on , with the brake cancelling it . Was yours a computer truck originally ?

    I found this : http://www.high-impact.net/transmission_and_gear/700r4lockupcontrol.htm
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

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  4. sickquad

    sickquad 1/2 ton status

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    It's electric and I don't think it is supposed to lock up in 3rd, only 4th.

    I'm thinking that having to control it with a switch is going to not be a good idea. Just if you forget to hit the switch when you hit the breaks.

    Why not use the knowledge of this board to trace down what the problem really is?

    The first question would be if your tranny is full of fluid? and how old is the Torque converter?

    -Chris
     
  5. sickquad

    sickquad 1/2 ton status

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    Would this work for you?

    click me

    -Chris
     
  6. dlaw36

    dlaw36 Registered Member

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    [ QUOTE ]
    I need to figure out how exactly to wire a torque converter lockup switch on my 700R4. I just want to put it on a manual toggle switch so I can kick the switch over when I am cruising on the highway so make sure the TC locks in OD.

    My TC only locks up randomly so I want to be able to override the system when cruising. Which 2 wires is it that I put on the toggle switch?

    I got a couple other questions too.

    Should the TC lockup when I am cruising in 3rd gear?
    How does the TC lockup work on an 85? Is it vacuum actuated or electrically activated? Thanks

    Harley

    [/ QUOTE ]

    What did you end up doing? I am having the same problem with my TC locking and unlocking at cruiz'n speed.
     
  7. lukebaby1

    lukebaby1 1/2 ton status

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    /forums/images/graemlins/thumb.gif
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

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    There was an article in a Hot Rod magazine that showed you how to put a switch in to override the automatic lock up,without disabling the automatic funtion,or the brake switch(so it wont stall at stop lights),but all my Hot Rod magazines got soaked in a heavy rain that flooded my shop,so I had to chuck them out--maybe they have a website you can search??.I think there are kits to put a lock up tranny in a vehicle that never had one,(TCI I think,mabe B &M) also a kit to change the speed it locks in at,preventing that annoying in-out-in out lockup from occurring while driving--how does the guy in front of you know exactly how fast to drive to make your tranny go into convultions anyway??? /forums/images/graemlins/confused.gifMy van drives me nuts when it does that! /forums/images/graemlins/angryfire.gif /forums/images/graemlins/angryfire.gif /forums/images/graemlins/screwy.gif
     
  9. Hossbaby50

    Hossbaby50 3/4 ton status

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    So far I have done nothing. I have adjusted my TV cable some to try and get lockup, but to no avail. I am probably going to take it back to my tranny guy and say fix it. If I don't I am going to put a manual lockup switch on the thing and call it a day.

    Harley
     
  10. dlaw36

    dlaw36 Registered Member

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    I may put a manual override on my TC also. I brought my tranny back to the guy that rebuilt it twice, and he could not tell me why it was unlocking/locking in OD. /forums/images/graemlins/dunno.gif

    Does anyone know if that is a complicated install?

    I have a 6.2 diesel - I guess that would not be an issue.
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    IIRC, the ALDL has a TCC lock terminal on it that when grounded, locks the TCC. FWIW, might help with things.

    If it's locking only randomly, I'd figure out why...it's not normal, and that system is pretty simple, even if the TCC solenoid is bad it's not a pain to replace.
     
  12. Hossbaby50

    Hossbaby50 3/4 ton status

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    I don't have the TPI running on a VSS yet so the ALDL method of lockup won't work. I am running the stock system from '85.

    Harley
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Stock system for the '85 is what, vacuum switch, and brake switch, correct? If it's not working correctly, unless the converter clutch is fried, it's gotta be one of those two, wiring, or the TCC solenoid, correct?

    I would think that system would be real easy to diagnose a problem in. Jumper vacuum switch while cruising with long wire leads, same for brake switch, TCC solenoid is pretty tough to check unless it sticks, which doesn't seem to be the problem here.
     

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