'67 Electra ST400 won't shift from 1-2

Discussion in 'The "Juice Box"' started by 67 Electra Cvt, Apr 5, 2021.

  1. 67 Electra Cvt

    67 Electra Cvt 18+ feet and counting

    I didn’t even realize it and hope I haven’t steered anyone down the wrong path.
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    In 1967, your Electra would have gotten the BT coded ST400. For all intents and purposes, it is the same as a THM400 EXCEPT that it is a switch pitch. The 2nd connection at the transmission is for the switch pitch feature (which does not work the way your car is now)

    You should verify that your car still has the original transmission. The tag on the passenger side of the case should look like this,

    An explanation of the switch pitch transmissions,


    BRUCE ROE Well-Known Member

    If you have a legitimate 67 400, the upper lug is for switch pitch,
    and the lower lug is kick down. You definitely do not want them
    shorted together. If you do not have the second wire to the upper
    lug, you are completely missing out on the features of a switch
    pitch. However, do try it with no wires connected. Bruce Roe
  4. 67 Electra Cvt

    67 Electra Cvt 18+ feet and counting

    I will check the tag on the side of the transmission, but after seeing the 'shoe heel' indent on the pan and the 2 blades for the electrical connection, I'm certain it is a ST400.
    I have not driven it yet without the disconnecting the wire to the trans. Hopefully, I can do that this week.
    If it is the governor causing the problem, can a new TH400 governor be used? And the same for the modulator?
    I am still looking for the SwitchPitch carb relay if anyone has one for sale.
    Thanks everyone for all your input and help.
    Last edited: Apr 27, 2021
  5. Quick Buick

    Quick Buick Arlington Wa

    For the heck of it. go to ebay.. buick lockdown switch... Hit the Used filter...... usually about 10 pop up... then by looking at the pic's figure out which one you have...... Hopefully the one on your car car is the one... from the pic it looks short... there are longs also... ETC ETC.
  6. Chi-Town67

    Chi-Town67 Gold Level Contributor

    mrolds69 likes this.
  7. telriv

    telriv Founders Club Member

    There is a switch pitch fix that eliminates the problematic switch on the throttle linkage at the end of the arm to a dashpot that takes the place of the stock dashpott in it's place. Eliminates also the problematic adjustmants.

    Tom T.
  8. 67 Electra Cvt

    67 Electra Cvt 18+ feet and counting

    Thanks for the replies. I might the dash mounted switch once I get the current issue sorted.

    Can a governor and a modulator from a TH400 be used in the ST400? If I'm going to check both, I'm thinking of replacing each while in the process.
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Yes. Instead of wasting your money, test your current components. There is a difference between auto mechanics and parts changing. The modulator is good if it holds vacuum and there is no ATF on the vacuum side. The governor is good if the weights and valve in the stem move freely.
    mrolds69 likes this.
  10. DaWildcat

    DaWildcat Platinum Level Contributor

    Spot on. And I've never had it happen to me, but if the modulator valves inside the valve body are stuck or only partially moving somehow, that could affect shift points even with a good modulator.

    See parts labeled 320-332.


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    mrolds69 likes this.
  11. Quick Buick

    Quick Buick Arlington Wa

    Just unplug the wire... Do you really need the passing gear kick-down? If the switch was inoperable the other way... ( no power getting though it ). Would you even know it was broke???????
    Personally highly dought it... Mine is missing the clip that holds the rod on the carb..... Im just to lazy to fab up another way to hold the rod on the carb... Also I did buy the modern vac switch but I dont know where I put it..
    Last edited: Apr 28, 2021
    mrolds69 likes this.
  12. mrolds69

    mrolds69 "The Cure"

    Shawn, I just saw this thread and I mostly agree with these guys. If the switch is not hooked up, and it shifted before, then it's probably something else like Larry, Bob and Devon sad. The modulator, valve behind it, the governor or vacuum. I'm not a trans guy (but I know of one in MA). I suppose it could be linkage, or cable stuff if it has a floor shift. Only you know what you messed with on it, since the problem popped up. I disagree with Tom, the dash pots are fine. Why re-invent the wheel? Two things: w/o looking at a wiring diagram, I remember that power wire is on a fuse for something else. Wipers? I forget, but if the fuse is blown... Second for Bob, that "top hat" clip is readily available.
    Quick Buick likes this.
  13. Quick Buick

    Quick Buick Arlington Wa

    Forget the fuse.... It the fuse is shot that would not the pitch switch (click noise) or the passing gear to engage (click noise)

    In the pic you posted the rod is missing.. the rod makes power go through the switch....Or removers power from switch......
  14. telriv

    telriv Founders Club Member

    Could be over time with no rod attached to the down shift/varible switch it has fllen down to the point where the system believes it's ALWAYS full, WOT, all the time .
    Another problem is the governer could be stuck at which time could cause the same problem. Easy to check & IF nec. take apart & clean.
  15. DaWildcat

    DaWildcat Platinum Level Contributor

    Agreed with above. Disconnecting the plug on the side of the trans takes the guessing out of the original electrical switching arrangement, well worth a try.

    To add to the "weird things" that can happen though, I've read of the detent (kickdown) solenoid getting stuck too! If that happens, taking 12V away won't help. Again, I've never seen it happen, but throwing it out there for more info.

  16. 67 Electra Cvt

    67 Electra Cvt 18+ feet and counting

    Thanks again for all of your input. I disconnected the plug on the trans and it now shifts. I still need the linkage at the carb. I'd like to restore it back to the factory spec. than add the switch on the dash.
    Now the bigger problem is miss firing. Never used to. Has a Petronix distributor on it. Checked all the wires and plugs. Fuel is brand new. I have to check the timing. I know this is a trans forum, but just wanted to update.

  17. 6769RIV

    6769RIV Platinum Level Contributor

    Depending on the Pertronix generation you may have asked and answered the same question. The early ones were terrible, mine only took a couple months before the misfiring and I instantly went back to points, never to return. "You'll never have to fuss with points again!" was a bad meme then and still is.
    Quick Buick likes this.
  18. Quick Buick

    Quick Buick Arlington Wa

    X2......... I bought a 67 special as a drivable parts car (floor rotted out)came with a pertronix. Got about 10 mpg. replaced with points 15ish mpg....

    With the distributor up front on the Buicks. Why bother with electronic kits...
    Last edited: May 4, 2021 at 9:03 AM
    6769RIV likes this.
  19. 6769RIV

    6769RIV Platinum Level Contributor

    God Bless you sir. :cool:
    This too. Even in the back, you just lean over from the fender, instead of the radiator and grille. Looking back now, easy to see the power of advertisement to invent a problem for every solution.
  20. 67 Electra Cvt

    67 Electra Cvt 18+ feet and counting

    I put in the Petronix electronic kit to replace the points only because I thought it was reliable. It has only been in the car for a year. I have to check to see if it is in fact the issue.
    Regarding the ST400, I was going to drop the pan and replace the filter because the pan is leaking. I was told I have to 'redimple' the bolt holes because the aluminum can become pulled when it was originally tightened. Has anyone heard of this?

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