020 gearbox leak

Discussion in 'Transmission' started by davkav, Oct 7, 2020.

  1. davkav

    davkav Paid Member Paid Member

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    I know there are plenty of posts regarding leaking 020 gearboxes but I can't seem to find the source of this one.

    I first noticed oil stains on the drive after a run in the car. On further investigation I discovered that a seal was missing from the clamp that holds the speedo cable into the gearbox. Replaced that and the leak still seems to persist.

    When I fit the gearbox earlier in the year, I filled it with fresh fluid via the speedo cable hole and only filled to until fluid ran from the filling hole on the side of the box.

    The photo below is gearbox oil that was left under my car after leaving it running for 10 minutes outside and then pulling it into the garage. I'm not sure if it is being released under pressure or pooling somewhere and then dripping down.

    IMG_20201007_102738_1.jpg

    There is no oil entering the cabin via the speedo cable but that doesn't rule out that oil is collecting on the cable and then dripping out after the car has stopped.
    The gearbox seems to be wet at the speedo gear hold and around the fill hole but that could be run off.
    I've checked the vent at the top of the box also and it is clear.

    I plan on opening the fill hole later today to see if any excess fluid runs out. Failing that I'll jack the car up and have a good look around.

    I'm starting to think rain water is entering it somehow as even if it was slightly overfilled, it should have settled by now; 8 months later...
     
    Last edited: Oct 7, 2020
  2. Tristan

    Tristan Paid Member Paid Member

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    Dry around the output shafts?
     
  3. davkav

    davkav Paid Member Paid Member

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    Yeah all dry around the shafts. I'm heading out now to open the fill plug and see what happens.
     
  4. davkav

    davkav Paid Member Paid Member

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    Speedo cable doesnt look too bad, certainly not wet enough for the amount fluid seen on the ground.
    IMG_20201007_120139.jpg

    Passenger side view
    IMG_20201007_120151.jpg

    And fill plug removed. A little bit of fluid ran out but nothing major
    IMG_20201007_120602.jpg

    And the speedo cable removed. Can anyone tell me if the O-ring #10A in this graphic is missing from my speedo type cable, or is it for another type?

    IMG_20201007_124800 (1).jpg
     
  5. Mk2daz

    Mk2daz Paid Member Paid Member

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    Any sign of oil around the green cap on the side around the 5th gear housing?

    I had an 020 that was leaking. It was coming from the output shaft seals and the green cap that I mention above.

    It could also just be the main casing gasket needs replaced!
     
  6. davkav

    davkav Paid Member Paid Member

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    Good point, I forgot to mention that. Green cap is bone dry also.
     
  7. Mk2daz

    Mk2daz Paid Member Paid Member

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    Oily around the clutch release arm? there is a seal behind it that may be going..
     
  8. davkav

    davkav Paid Member Paid Member

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    I've checked that too, and pulled the boot on the gear selector itself and everything seems fine. Keep em coming though :hug:
     
  9. Tristan

    Tristan Paid Member Paid Member

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    You're going to have to clean the box with a pressure washer and something like brake cleaner or petrol, get it all dry and then see. You might just have a weep at a gasket.
    I had a tiny crack in an 020 housing once on my old Caddy.
     
  10. Tristan

    Tristan Paid Member Paid Member

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    Any clutch slip?
     
  11. davkav

    davkav Paid Member Paid Member

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    Surprisingly no, see below

    So I got the gearbox out. On closer inspection it looked like the oil was coming from the driver side of the box
    IMG_20201008_115945.jpg

    And sure enough the culprit is the input shaft seal is leaking. The gearbox oil must be collectin the bell housing and then dripping out when the car is stationary
    IMG_20201008_210524.jpg

    New seal will be ordered and that should sort it. Ill give the box a good scrub too whilst it is out of the car.
     
  12. rubjonny

    rubjonny Administrator Staff Member Admin

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    get a new pushrod bush and seal at the same time
     

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