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TH400 Kickdown Switch

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Panther212, Apr 14, 2003.

  1. Panther212

    Panther212 Registered Member

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    When I first got the 78 back in December, there was a lot of crappy wiring that hung around from under the dash and more. Well recently after pulling the TH400, I realized that I must have accidentally pulled the wiring to the kickdown switch.

    How can I rewire it? I've still got the switch all set up, just the wiring's gone.

    Oh yeah, and have I been causing damage to the tranny w/o this? Whenever I'm reving down from a high rpm I always throw it into neutral now, just to be safe.

    Any info is greatly appreciated /forums/images/graemlins/thumb.gif
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    No you aren't doing any harm. It's there solely to "kick down" from 3 to 2 (AFAIK not 2-1) when the pedal is depressed a certain distance, such as when you need to pass.

    I drove a TH400 (hard) for years behind a 403 without kickdown, and it never failed.
     
  3. MTBLAZER89

    MTBLAZER89 3/4 ton status GMOTM Winner

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    If ya got a strong motor just scrap it. More reliable because if the wiring gets broken but it's still hooked to the tranny it will shift all fawked up. Just my .02
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Doesn't affect shifting quality/consistency one bit, only the downshift. There is NO other point to the kickdown. Once the pedal isn't touching it (and for most of us, thats 95% of the time), it's out of the equation.
     
  5. Panther212

    Panther212 Registered Member

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    To me there's quite a difference without it though, does anybody know how to rewire it? Looks like a spade connector through the switch, but do I just give it positive power or what? Do I not need a ground since the tranny itself is connected to a ground?

    Thanks for the info, it's good to know that I won't screw anything up!
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Do a search for "wiring diagram" on this board. MJ has a couple of years wiring manuals in a webshots album, believe TH400 wiring should be shown in it.
     
  7. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    One side of the switch goes to switched ignition power. The other goes to the spade connector on the side of the tranny. Its really simple.

    John
     
  8. DieselBurb

    DieselBurb 1/2 ton status

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    By the way, I've always been told that automatics don't like to coast in neutral....

    Diesel /forums/images/graemlins/burb.gif
     

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