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Thread: Any Tricks to slow Dynaflow leaks

  1. #1
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    Any Tricks to slow Dynaflow leaks

    Hey guys not sure where to post this, but I've been under my 55 Special a lot this week, trying to get it read for Led East, this might be the year it makes it. I've been really fortunate all these years my Dynaflow never leaked. Well the other day I was under it and it looked like it was leaking by the "tailshaft" and it's actually low. The car sat for 30 years before I got it 10 years ago, so out of fear of moisture I changed the fluid and put in Dex Merc high mileage and it was never a problem. Then it sat for about 3-5 years so I changed all the fluids again and this time I used straight Dex Merc because the car only has 35k miles on it Could it be the fluid or coincidence? Is there a trick to get the seal to swell up again? I know the Dynaflow is a strange beast so I don't want to just be throwing stuff into it without asking guys who know.

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    If the transmission has never been touched, the outer torque ball retainer is metal which formed sort of seal with the torque ball. Replacements are better with rubber vulcanized to the outer torque ball retainer.
    External leaks are messy and can be monitored, but internal are a bigger problem: the seal at the end of the torque tube was originally leather and is past it's prime. Leaks here allow fluid into the torque tube and sometime into the rear end by way of a defective pinion seal (leather also).
    The available outer torque ball retainer kits have the torque tube seal also. I drill a hole in the torque tube about 1.5 inches in front of the rear flange to monitor fluid in the torque tube.
    You can slow down minor leaks by adding a (blue) bottle of STP.
    The factory service manual is your friend!

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    The only way to stop a Dynaflow from leaking is to let it all leak out. I drove my dynaflow for years and it always leaked, over the winter (6 months it would leak about 2 quarts) but it was dependable never failed me in over 100,000 miles. When I would drive it to a car show or somewhere where I did not want to have a mess on the ground I would take a cotton towel and fold it up and I would place the towel under the leak and tie it up with nylon ties. That will catch all the oil and you will not be embarrassed with a mess. You can not stop a dynaflow unless you run it out of fluid. I always used the GM Ford combination transmission fluid. Just do not put any of that stop leak stuff in your transmission it makes all the seals expand, then they contract. Mechanic in a bottle, bad idea.

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    Quote Originally Posted by 322bnh View Post
    If the transmission has never been touched, the outer torque ball retainer is metal which formed sort of seal with the torque ball. Replacements are better with rubber vulcanized to the outer torque ball retainer.
    External leaks are messy and can be monitored, but internal are a bigger problem: the seal at the end of the torque tube was originally leather and is past it's prime. Leaks here allow fluid into the torque tube and sometime into the rear end by way of a defective pinion seal (leather also).
    The available outer torque ball retainer kits have the torque tube seal also. I drill a hole in the torque tube about 1.5 inches in front of the rear flange to monitor fluid in the torque tube.
    You can slow down minor leaks by adding a (blue) bottle of STP.
    The factory service manual is your friend!

    322bnh everything is original and has never been apart. I actually know the last owner very well and he has owned it since 1968. Are you talking about the blue STP you would pour in engine oil? or is there another one that is for transmission fluid?

    suntreemcanic What do you mean by combination fluid?

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    Smile

    Quote Originally Posted by My55buick View Post
    322bnh everything is original and has never been apart. I actually know the last owner very well and he has owned it since 1968. Are you talking about the blue STP you would pour in engine oil? or is there another one that is for transmission fluid?

    suntreemcanic What do you mean by combination fluid?
    Yes the blue bottle for engines. I have used it since the 1960's when it still had directions for tranny use on the label. When I told my mentor about it (and was expecting a lecture) he said it would not hurt and he used it all the time. It just increases the viscosity to slow leaks and improve pump pressures.
    Combination fluid? Hopefully he is refering to Dexron III/Mercon and NOT mixing Type F with any GM fluid.
    All of my dynaflows (3) are dry and don't need a diaper....it can be done!
    Drill the hole at the back of the torque tube to see what is in there...if transmission fluid then keep it drained so that it does not get into the rear gears which will be destroyed if too much.
    If it is unknown whether the axle seals and bearings have been done recently do that now.

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    I used the wrong word, it is multi-purpose automatic transmission fluid. I had my Buick which the manual calls for Type A which is no longer available but Dexron III is equivalent and I had a Ford that required Mercon. There on the shelf was STP brand Multi-Purpose automatic transmission fluid designed for GM cars requiring Deron III and Ford vehicles requiring Mercon. I no longer have the Ford but I kept using the Multipurpose Fluid because my Dynaflow was working good. I have never used many STP products except for the transmission fluid but I felt they were well engineered.

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