1966 ST300, When should it shift?

Discussion in 'The "Juice Box"' started by ancientx, Jul 7, 2009.

  1. ancientx

    ancientx horn/antler&bone carver

    Hi guys. I can't seem to find any info as to when my tranny should shift. Well, outside of 65 @ WOT.
    My uncle has been a BOP guy all his life. (Minus the P.:pp )
    Now he says that at an easy acceleration, it ought to shift at around 20 mph. My problem is that it won't shift at all until 65WOT.
    This is decidedly not cool. My gas mileage is not as good as it could be and I really don't want to burn up my tranny.
    I do have a cooler added.
    I also replaced the vacuum modulator.
    I figured out how to get the kick-down hooked up as I have a Carter AFB comp. series carb. I don't think the little switch on the back of the trottle linkage is working though.
    Could that be the problem?
    Could it possibly be the governor?
    :Do No:
     
  2. 65specialconver

    65specialconver kennedy-bell MIA

    Look for a vacume leak in the line from the intake to the trans.Those rubber spacer hoses often crack.My ST300 shifts about 22mph:TU:
     
    Last edited: Jul 8, 2009
  3. LARRY70GS

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

    The ST300 has an electric kickdown just like the 400. There is a dowshift solenoid inside the pan. If it is constantly energized or stuck in the open position, the trans will not upshift except at WOT. Something else to consider.
     
  4. ancientx

    ancientx horn/antler&bone carver

    Thanks for responding Larry. (I was kinda hoping you'd respond:grin:)
    I checked the solenoids to see if they worked by running a hot wire to the leads on the tranny. They work. (Thanks to one of your posts I knew how to do this.:TU:)
    The top lead, horizontal, gets power. But the vertical doesn't. Even manually manipulating the sp switch on the throttle doesn't get power to it.
    Could that be it?
     
  5. ancientx

    ancientx horn/antler&bone carver

    I do plan on getting Bruce Roe's set-up for the car in the next few weeks.
    I'm hoping that will eliminate a few problems.
     
  6. ancientx

    ancientx horn/antler&bone carver

    Thanks, I'll check that in the morning too.:bglasses:
     
  7. d2_willys

    d2_willys Well-Known Member

    I agree 100%! I was going to suggest this, but larry beat me too it! Good job Larry!:bglasses:
     
  8. LARRY70GS

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


    The horizontal is the stator control, the vertical is the kickdown. Apply 12 volts to each one and listen for a click as the solenoid energizes, and a click as it de energizes. If you don't have a vacuum leak in the modulator line, I would change the kickdown solenoid. It may be stuck open.
     
  9. ancientx

    ancientx horn/antler&bone carver

    Yep, did that, both kick on when power is applied and kick off when power is removed.
    I'm going to get some new vacuum line and replace whats there and see if that makes a difference.
    I'll do a couple of other little "tests" to try and diagnose this, and get you guys more info to work with.

    *sigh* "Cars or women" my Dad said. "Both will cost you, both are a depriciating investment, but at least the car doesn't argue back."
     
  10. d2_willys

    d2_willys Well-Known Member

    If you have a vacuum gauge hook this up to the vacuum hose at the modulator and read the vacuum at idle. Should be around 18".:blast:
     
  11. ancientx

    ancientx horn/antler&bone carver

    I'll try that and see what it is.
    Also, I found that the "T" connector was so loose that it wouldn't keep the connection. So I cut it off and added a female to each wire. Now, with the key on, my uncle opening the throttle, I can hear the solenoid kicking on and off.
    Still isn't shifting so I think I might need to turn the modulator down. It's new so I "know" it isn't bad.
     
  12. LARRY70GS

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

    I wouldn't adjust anything until I verified that the vacuum at the modulator was the same as at the intake. Just takes a few minutes. Keep it simple first.
     
  13. ancientx

    ancientx horn/antler&bone carver

    Gotcha.:TU:
     
  14. ancientx

    ancientx horn/antler&bone carver

    Well, it reads 16. Is that too little?:Do No:
     
  15. LARRY70GS

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

    It is for a completely stock engine. Vacuum depends on what cam the engine is using. For a stocker, I expect closer to 20"
     
  16. ancientx

    ancientx horn/antler&bone carver

    That particular vacuum line is attached to a little "stud" that threads into the intake manifold centered behind the carb. Is this the correct placement?
    Should I try another spot? If so, where?
     
  17. LARRY70GS

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

    No,
    I'm sure that is manifold vacuum. You didn't answer my question, stocker, or cammed?
     
  18. ancientx

    ancientx horn/antler&bone carver

    So sorry. To be honest, I'm not sure. I bought the car and the motor from a guy who spun the bearings in the original 340. He bought a crate '71 buick 350. He said the rebuild place offered options as to how a person could have it built.
    He also told me that they tested it at 410 horses. That doesn't sound stock to me, but what do I know?
    I have the paper work they sent him, but there isn't anything in there showing what went into the engine or a dyno sheet showing any "test".
    Personally, I bet it's stock. But once again, what do I know?
     
  19. ancientx

    ancientx horn/antler&bone carver

    I'll be back on in a while. For personal reasons, I need to get off the computer for a while.
     
  20. ancientx

    ancientx horn/antler&bone carver

    Well, I was off a lot longer that I thought I would be.
    I also just found that my vacuum advance's diaphram was shot so put in a new one. I had hoped that that might make a difference in shifting, but no such luck.
    Anyhow, since the carb is perfectly tuned and I'm fairly certain the timing is set right, I can hear whats going on better.:TU:
    I noticed that while it's still not shifting, there are times while driving that I need to tap the gas to get the rpms to drop down to normal. I think this is due to either the kick down or the sp switch sticking.:Do No:
    Out on the property there's a '65 Olds w/a st400 in it. I'm going out tomorrow,cutting my way through the jungle and getting the kickdown and sp wiring off of it. That might fix my problem.:pray:
    Or not.
    If it does, it still doesn't explain what the problem was(is).
    If it doesn't, I'm no worse of than I am now. Well, except for chiggers and ticks.:rant: :blast:
    Has anyone ever bought a bad modulator before?
     

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