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Thread: problem with overdrive

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    problem with overdrive

    tr3 with a tr4 trans with od. the od pops in, but doesn't let go. even if i power off the car, the solenoid does not release. if i remove and replace the solenoid, it again pops in but not out. i have another tr4, where the od works fine. i notice on this car that there is some sort of downward pressure on the od lever. there is none on the tr3. if i swap the solenoid units, it makes no difference in either car. the tr3 is getting power obviously to the solenoid; tested that.

    am i correct in assuming that there is some sort of spring mechanism in the od that causes it to release, and that has failed in the tr3? and that i have to pull the tran, pull the od, and fix that? i'm assuming i can't remove the od from the tran while its still in the car?

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    Yoda glemon's Avatar
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    Re: problem with overdrive

    Don't despair yet, although there are differences in the different types of overdrives they offered over the years, I believe you can access the actuating ball and lever arrangment these things have with the tranny in place and the tunnel off, at least I could on my old Healey 100.

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    Re: problem with overdrive

    The solenoid plunger should fall back down just from it's own weight. Sounds like you have something binding that shouldn't bind. There is a small spring above the valve that pushes the lever down a little bit, but it's not very much and only works on part of the movement.

    Try removing the plug above the operating valve, and fishing the stem out with a bent paper clip. At that point, there is nothing connected to the rod that gets turned by the solenoid, so it should move freely. You say you've already swapped solenoids, so it's not the solenoid binding. Also check that the arm is not rubbing on the side of the OD. There is a spacer that goes between the two, which might have gotten overlooked during assembly.
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Re: problem with overdrive

    While you have the operating valve stem out, you might try blowing out the passages in it. If they are clogged, the od will be slow to disengage, or not disengage at all. Also, you might check the actuating bolt stop adjustment, mentioned in this article from the Buckeye site. https://www.buckeyetriumphs.org/tech.../AOD4/AOD4.htm
    Another possibility is that the sliding clutch is stuck to the brake ring. Usually, just a whack on the brake ring is enough to free it and you can hear a click to confirm.
    Berry
    Last edited by titanic; 03-05-2016 at 11:50 PM. Reason: error

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    Re: problem with overdrive

    there is a little adjustable lever that is attached to the overdrive on the drivers side that is attached to the od solenoid. it is mirrored on the passenger side by a fixed lever. this lever has to be adjusted just so, otherwise it will bind on the vertical trip, either up or down, or will not create pressure on the spring that causes it to return (the spring is inside the od). the lever on the passenger side is essentially a tool to help you ensure that it is just so, allowing you to move it up or down in your testing. this was not "just so" and therefore did not work. with some adjusting and banging, i got it to be "just so." The overdrive is now working!!!

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    Re: problem with overdrive

    I was going to say...I noticed that the factory setting for that adjustment is a bit tight. I had to loosen it a bit more than spec to get the OD to engage/disengage consistently. I think it is due to wear on the actuating shaft and it's bore...you lose a little of the motion as it transfers from the solenoid across to the actuating arm in the OD.

    Glad it's working!
    John

    1955 TR2

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