Turbo 350 leaking when not running

Discussion in 'Troubleshooting & Diagnosis' started by rocket dawg, Sep 13, 2019.

  1. rocket dawg

    rocket dawg Veteran Member

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    Seems to be on the passenger side of the trans, probably the dipstick or the cooling lines. Does not leak when hot and running. Sent the car into a trans shop to fix all the leaks and mechanic couldnt get at the large round seal ( accumulator? ) on that same side because the header/exhaust was in the way. Seems to me that part is high enough that it wouldn't leak while not running. I replaced the dipstick and seal with something similar to this one seal wise (cant find the exact one I bought.) The leaking is getting worse. I've had daily driver 350's that never leaked a drop, probably 5 different ones over the years. Gonna drop the trans this off season and replace whatever needs to be replaced. I need a dipstick that dont leak. I stored the car for years without it leaking, now it leaks overnight and it's more than an occasional drip, it leaves a puddle. thanks seal is listed below from summit


    https://www.summitracing.com/parts/ado-1259475
     
  2. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    Fluid flows back from the converter and the level is higher when it's sitting.

    TH350 transmissions used a couple of different dipstick tubes and seals over the years.

    One had an O-ring which fit into a groove in the dipstick tube and seated in a grove in the transmission case.
    Others used the top-hat seal. (Which is what you linked.)

    The top hat design won't seal properly in a transmission designed for an O-ring seal.

    You'll need to check the tube and case for that groove and use an O-ring seal if that's what you have.
    Even then... You may need to use some hi-temp RTV to get it to properly seal.
     
  3. rocket dawg

    rocket dawg Veteran Member

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    Yes, it originally had an O-ring tube on it. Interesting. Anyone spend the big dollars and get a Lokar flex tube? It needs the pan dropped because a fitting goes inside. If I drop header or the exhaust, is it difficult to replace the accumulator O-ring? Trans fluid is thin and the whole side of the trans is wet and really hard to pin point the leak. thanks for the info!
     
  4. cadillac_al

    cadillac_al Veteran Member

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    I replaced an O-ring dipstick tube with the hat style and solved my leak. I don't think your seal should be leaking.
     
  5. larrylarry

    larrylarry Veteran Member

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    Accumulator o ring is easy to change. When you remove it you have a flood of trans fluid coming out. The trans pan bolts are only around 10 ft lbs of torque, something to remember.
     

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