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Thread: Overdrive dummy mainshaft

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  1. #1
    Senior Member
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    Jun 2012
    Lengerich, Germany
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    Overdrive dummy mainshaft

    Dear friends

    When assembling the overdrive, sun gear and unidirectional clutch must be positioned exactly to each other. For this, the removed transmission main shaft can be used or the service tool 1G185 is used as the dummy mainshaft.
    Since I have both parts unavailable, I'm looking for ways to make a dummy mainshaft myself. Has anyone made one? What are the dimensions and what materials can be used to make the shaft the best?
    About a dimensional drawing or a photo, I would be happy.


    Austin Healey 3000 MK III BJ8 (in Frame off Restoration)
    Triumph TR3 (Frame off restored)

  2. #2
    Jedi Knight Healey Nut's Avatar
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    Sep 2013
    Ottawa Ontario
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    Re: Overdrive dummy mainshaft

    You dont need the dummy shaft , with the gearbox upended onto a stable flat surface so the mainshaft pointed down .
    Take the assembled overdrive unit and using a long pointed screwdriver feel with the tip to make sure the double splines are exactly aligned inside the OD .
    Then using another short bladed screwdriver and some tie wraps you insert the screwdriver through the side of the OD (accumulator access plate removed) to lever down on the oil pump spring so the plunger retracts a bit . Put the oil pump drive cam 180 degrees away from the pump plunger .
    Use the tie wraps to secure this screwdriver in place around the side cover studs and maintain the leverage on the oil pump spring inside the OD .
    Now carefully and slowly without forcing anything lower the OD onto the gearbox .
    If everything is aligned (including the stars) the OD will fall into place .
    Put on the nuts tighten it all up and celebrate with a couple of cold ones .
    I have done this several times , it gets easier after about the 4th go .
    Good luck .
    "If it aint broke ....dont fix it "
    " Thats not an oil leak ..........its a special automatic British rustproofing system "
    Best Healey in show ABCD Ottawa 2013
    Best Healey in Show Boot n Bonnett Kingston 2013


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