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lock up torque converter

Discussion in 'The Garage' started by gmcman, Jan 20, 2007.

  1. gmcman

    gmcman Registered Member

    Apr 7, 2006
    Likes Received:
    Red Deer, Alberta, Canada
    I have a '67 gmc 1/2 ton 2wd pick-up.It has a 305 4bbl with a th350 with no lock up converter.The rear-end has 3.73 gears-not good for the highway.I was given a newer th350 with a lockup converter and was wondering how much trouble it would be to install this tranny and hook up so the converter would lock up.I realize that i would not drop my rpms much but every little bit would help.Always feels like it needs another gear.I think i need a switch on the brake pedal to unlock it when you hit the brakes,correct? There is only one wire on the tranny and i assume this is for the converter.Do i just hook this to 12 volts? Does the tranny do the rest?Does it lockup after a certain speed and unlock when you slow down or press on the throttle?Or is there another eletronic box or something that controls this? I could use a 700r4 but was really just curious how these th350s with a lockup work.Any help would be greatly appreciated!
  2. b454rat

    b454rat 1/2 ton status Premium Member

    Jan 21, 2003
    Likes Received:
    Binghamton NY
    Easiest way would be to hook up a toggle switch. Around town or alot of stop and go, leave it off. When you get out on the highway or open road, flip it on. GM used a vacuum switch to turn it on/off, probly snag one from a j/y.
  3. obijuan

    obijuan 1/2 ton status GMOTM Winner

    May 18, 2006
    Likes Received:
    San Antonio TX
    you can call bowtieoverdrives.com. i had questions regarding lockup and they helped out so much. they are very knowledgable about their parts and compatibility. they may know exaclty what you need.

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