transmission cooler line fittings sizes?

Discussion in 'The "Juice Box"' started by racerxjj67, Aug 22, 2018.

  1. racerxjj67

    racerxjj67 Well-Known Member

    Anyone know the fitting/thread size for the trans cooler line in a 68 BOP turbo300 powerglide? Having a hard time finding the correct thread fittings.
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Are you talking about the fittings that actually screw into the transmission case?

    I believe these are the stock type fittings,

    The metal transmission cooler lines are 1/2-20 inverted flare at the above transmission fittings and at the radiator as well.
    Last edited: Aug 22, 2018
  3. racerxjj67

    racerxjj67 Well-Known Member

    yes the ones that screw into the case. Thanks. I'm having a hell of time getting them back in.
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Be careful, if you use the wrong fittings, you could damage the case/threads.
  5. racerxjj67

    racerxjj67 Well-Known Member

    It's the same lines and fittings that were on it originally. Took them off during engine rebuild and can't get them to bite to put back on. Ugh. It's the only thing holding me back from getting it on the road now.
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Are the threads in the case damaged? Threads of the fittings?
  7. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Those flare fittings are sometimes tricky to get started, if you don't have them almost perfectly square and centered to the hole you will have a hard time getting them started. You need to be careful not to force them either or you can cross thread them and they'll leak very badly.

    Sometimes the lines bend when they are removed and aren't bent the right way anymore to get the threads to engage, you sometimes have to grab the line with one hand to try and center it while trying to screw the fitting in with the other hand.

    If that's still not enough, if they are inserted into the radiator already, it may be easier to get the trans end to engage if the radiator end is disconnected.
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    So I am unclear whether we are talking about the lines engaging the fittings or the fittings engaging the transmission case?
  9. Mart

    Mart '71 350 GS, almost stock

    So am I.
    There is a brass fitting on trans, then a flare trans line fitting that fits into the brass one.

    Maybe the 300 trans doesn't have both?

    BRUCE ROE Well-Known Member

    Its a mechanical skill test. I have seen (and own) fittings for both 5/16 inch and
    3/8 inch lines, they seem to interchange in the case. Bruce Roe

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