Help: Car is having trouble shifting!

Discussion in 'The "Juice Box"' started by MR.BUICK, Oct 25, 2004.

  1. MR.BUICK

    MR.BUICK Guest

    Well, I know the best solution to have this fixed, but before I do anything like that I would like to find the problem so if I come to another experience like this again I will be a little knowledgable of it. Anyways, heres the problem: After the car is warmed up, after its been driving awhile if you go up a hill or a slope it will start to downshift, then it will upshift, then it will downshift, then upshift, untill your out of the slope or hill, it will keep doing just that. And it feels like it keeps going into passing gear and wont let up untill I let off the throttle/accellerator. Weird. The car never used to kickdown wildly like that, and not only that, but if im going straight it will do it then as well, if im going 20 mph and want to go a little faster all I do is slightly baby it and it will still do it. Anybody have any idea of what it might be? I want to get it fixed.

    Thanks

    -Cody
     
  2. LARRY70GS

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

    Cody,
    It would really help to know what transmission you have. Is it a THM-350? If it is a 350, check that the downshift cable and linkage isn't jammed or adjusted wrong. If it's a 400, check that the downshift solenoid isn't stuck open.
     
    Last edited: Oct 25, 2004
  3. MR.BUICK

    MR.BUICK Guest

    I tried to search to find out what kind of tranny it is, but I can't find out, looked in the owner's manual and couldn't find it there. So all I know is it is a 3 speed automatic, im assuming TH-350(???). Thanks
     
  4. LARRY70GS

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

    OK, look down at the gas pedal. There should be 2 cables attached. One is the throttle cable, the other is the transmission detent cable. You should be able to pull the detent cable about an inch or so, then when you let it go, it should pull back into the transmission. If you cant pull it out, the cable may be sticking, or the linkage inside the pan may be bent/damaged. In any case the the downshift mechanism may be jammed in or close to the downshift position causing the problem. If it is jammed, drop the pan and investigate.
     
  5. MR.BUICK

    MR.BUICK Guest

    Thanks Larry, I'll take your advice and do that tommorow. Im planning on a rebuild anyways, but i'd like to have some kind of knowledge as to what this specific problem is and if I can determine it by checking things I might find the problem.

    Thanks
     
  6. MR.BUICK

    MR.BUICK Guest

    Checked it today...seems to be the detent as it won't pull back any, called my mechanic and told him my troubles and told him about how I checked my detent wire seems to him it is bent/damaged as well, so he said to drop it by tommorow and he'll inspect it to make sure that is the trouble. Thanks for the info. Will keep you updated...
     
  7. MR.BUICK

    MR.BUICK Guest

    BTW, my car has a TH-350 in it, contaced mark sedran(guy whom owns a 1976 buick century himself; like mine) and he said that's what they came with.

    Like I said I will keep this updated when the problem is located. Thanks!!!
     
  8. MR.BUICK

    MR.BUICK Guest

    Update: Today went to my mechanic and told him that I think it is the detent wire, so he looked around the accellerator, found the cable, tugged on it, and to my surprise he got it to pull loose and let it go back in, pulled it back, let it slide back in and did a little while to make sure it was loose and not stuck as it was when he pulled it. So after I thanked him and everything, we took the car out awhile to let it get good and warm, took it on a few slopes, and some pretty big hills, and the car made it up them hills/slopes as if they were nothing. Runs just like it's supposed to now. I can't thankyou enough for the advice/info. Larry, Thanks :beer Im glad you told me to try that first before I did anything else.
     
  9. LARRY70GS

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

    Excellent! Glad it worked out for ya.
     
  10. GoldBoattail455

    GoldBoattail455 462 -> TH400 -> Posi

    Glad it wasn't serious Cody.

    And to think you were gonna sell you Buick. :spank: :moonu: :pp
     
  11. MR.BUICK

    MR.BUICK Guest

    :laugh:

    Glad I didn't, especially since it was something as simple and little as that. :Dou: Like I said before a few times this car will make a good beginners/learner project car :3gears: :TU:
     
  12. MR.BUICK

    MR.BUICK Guest

    Well, it's back to doing it again, thought id try a few things before I say anything else on here...didn't work. When I pull on the detent cable, it goes back in, but therefore it makes the car harder to kickdown and takes it longer since the automatic choke in the carb. is worn out and dont work, as far as driving goes if i dont pull the cable before I go it starts to kickdown tremendously again. Seems to be loose. Any solutions?

    TIA
     
  13. LARRY70GS

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

    Cody,
    You are going to have to drop the pan, and take a good look at the detent linkage. If it isn't a mechanical problem, you may be looking at a rebuild. Shop around, a rebuild on a THM-350 should be very reasonable.
     

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