Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Single wire on TH400 trans. What is it too?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by cybrfire, Jan 20, 2003.

  1. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

    Joined:
    Dec 15, 2002
    Posts:
    15,143
    Likes Received:
    579
    Location:
    Iowa
    My donor truck was a 1982 deisel 3/4 ton truck. When I pulled the trans I noticed a single orange wire attached to the driver side of the trans. Does anybody know what it is for? Thanks.
     
  2. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    It goes to a switch on the accelerator bracket that tells the tranny when you've mashed the loud pedal. Then the tranny goes into passing gear. /forums/images/graemlins/cool.gif
     
  3. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

    Joined:
    Dec 15, 2002
    Posts:
    15,143
    Likes Received:
    579
    Location:
    Iowa
    So with this trans there is no cable operated kickdown Correct? I wonder how I get that switch to work on my setup. I don't have that switch on my carb. Is there an aftermarket switch?
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,188
    Likes Received:
    1,395
    Location:
    E-town baby!
    Rob the switch from the parts truck...

    Rene
     
  5. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

    Joined:
    Dec 15, 2002
    Posts:
    15,143
    Likes Received:
    579
    Location:
    Iowa
    gone and crushed. Not sure I could pry it out of that ball of steel. hehe. Thanks anyway. I will get a replacement one. Thanks for the info though.
     
  6. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    The switch is mounted on the gas pedal bracket, under the dash. The holes for the screws should already be there on your bracket. /forums/images/graemlins/cool.gif Grab the switch and wiring from any other rig with a Turbo 400. I got mine from an old Jeep Wagoneer. /forums/images/graemlins/cool.gif
     
  7. imiceman44

    imiceman44 1 ton status

    Joined:
    Aug 5, 2002
    Posts:
    15,160
    Likes Received:
    1
    Location:
    Sacramento, CA
    Yeah it's on the gas pedal braket and mine is in the wagoneer. /forums/images/graemlins/thumb.gif
     
  8. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

    Joined:
    Dec 15, 2002
    Posts:
    15,143
    Likes Received:
    579
    Location:
    Iowa
    I guess I assumed it was on the linkage on the carb. Is this something a guy can just hook up to a momentary switch and a 12volt power supply?
     
  9. R72K5

    R72K5 Banned

    Joined:
    Mar 5, 2001
    Posts:
    8,905
    Likes Received:
    0
    Location:
    central IL
    no because you will be moving gas pedal alot and need it on and off often

    find a switch i have one im gonna see if you want to buy off me, i have entire accelerator assembly with switch intact and all off a 74 works good, check your PM's
     
  10. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Hooking it up correctly is FAR too easy to even monkey around with a hack job. Get the right swtich and you can have it all installed properly in about 15 minutes. /forums/images/graemlins/thumb.gif
     
  11. imiceman44

    imiceman44 1 ton status

    Joined:
    Aug 5, 2002
    Posts:
    15,160
    Likes Received:
    1
    Location:
    Sacramento, CA
    Well all it does is the kick down shifting, and the upshifting is controled by the vacuum modulator.
    When mine was unhooked, by mistake, I felt it wasn't working so I downshifted manually and it was actually smother and better for the tranny.
    You can do that while you get the parts.
    I still do even after putting the line, sometimes because my gearing is too tall, I downshift to keep the engine in the sweet spot.
     
  12. BurbLover

    BurbLover 1/2 ton status

    Joined:
    Jul 31, 2001
    Posts:
    3,060
    Likes Received:
    0
    Location:
    SW Missouri
    Just hooked mine up last week after a 700 to 400 swap. A new switch was 30 at the local Chevy dealer. When I called to get a quote, they said 22. So when I went in & was told 30, I bitched. They sold it to me for the 22. Just hook one lead to the fuse box with something that comes on with the ignition & run the other through the firewaal to the trans. I ran mine where the speedo cable goes. Anyway, make sure you don't run the wire too tight to allow for flex & later mods (body lift?). This was the easiest maintenance work I ever did on my Burb. The only problem I had was the switch barely moved when the accelerator pedal went all the way down. Fixed this by putting a piece of hose over the switch part & it works like a charm. Hope this helped, or at the very least, didn't hurt!!!
    /forums/images/graemlins/burb.gif /forums/images/graemlins/thumb.gif
     
  13. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Wow! And I thought I got ripped when the yard wanted $5 for the switch, screws and wiring! /forums/images/graemlins/eek.gif /forums/images/graemlins/wink.gif
     

Share This Page