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Technical LEAKING CHEVY TRANS

Discussion in 'The Hokey Ass Message Board' started by 48coupe, Apr 7, 2016.

  1. Trans. (C 350) does not leak until I park it for awhile, then I get a gal. ++ on the floor. It appears to be coming out the filler tube hole. We have had the trans. out twice thinking we had it fixed. Could the convertor oil be draining out after sitting ( 3-4 wks.) ?? Right now we are at a loss of where to ck further.
    Thanks for the help.
    Wes
     
  2. So, you are saying that the fluid comes all the way up the filler/dipstick tube and then 'pukes'?
    That would be a lot of fluid and it would seem that if that was so it would come out the air breather tube and if so you might be overfilled. As the trans takes an X amount of fluid in the system to operate and when you shut it down, it drains down into the trans....

    "I am not a trans Doctor, I just play one in my shop......."
     
    olscrounger and hotrodharry2 like this.
  3. cshades
    Joined: Sep 2, 2011
    Posts: 472

    cshades
    Member
    from wi

    my ot plow truck and my avatar have done that ever since I can remember. The avatar sits all winter so I put a catch pan under it and the plow truck sits all summer and pukes its fluid in the storage building floor. Have never been able to get it to stop so I will watch for any ideas on how to get it fixed.
     
  4. 33essex
    Joined: Aug 21, 2015
    Posts: 171

    33essex
    Member

    Chevy transmission? we have this problem at my work after any or most of the chevys or chevy powered sit more than a week or 2. The floor will have a huge puddle of oil. Now this is what i was told causes this. I don't know for sure, but a older fella I work with said . The torque converter dumps it's fluid back in to the case after sitting for awhile. So this causes any seals to leak or leak more than just running it. They will leak around the dip stick tube shifter shaft,tail seal ect. Like I said don't know if this true.
     
    Last edited: Apr 7, 2016
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  5. statesblue
    Joined: Mar 5, 2008
    Posts: 253

    statesblue
    Member
    from Luzerne Pa

    I'm with typo41 on this. That would be my guess also. Take it for a ride and get the trans warm then check the fluid level while the motor is at idle.
     
  6. HOLLYWOOD GRAHAM
    Joined: Apr 11, 2007
    Posts: 1,404

    HOLLYWOOD GRAHAM
    Member
    from Ojai,Ca

    I know you probably did this but did you put a new O ring on the bottom of the tube?
     
  7. ROBERT JAM
    Joined: Nov 13, 2002
    Posts: 1,178

    ROBERT JAM
    Member

    Torque converter leaks down then fluid leaks from the dip stick where it goes into the pan. A little oil always looks like a lot on your floor. It's happened to me, and now I just start and run the car every once in a while while I is put up for the winter.
     
    hotrodharry2 likes this.
  8. What Robert Jam said, Torque converter leaks down will leak from dipstick,around the shift arm and speed odometer cable. just start it ever so often, Turbo 350 seems to do this more, than others
     
  9. Dave 39
    Joined: Jul 24, 2006
    Posts: 54

    Dave 39
    Member

    I have two cars with th-350. One never leaks a drop, the other drains back from the torque converter after a week or so. Took my suction gun and pulled a quart of fluid from the pan; no more leaks. Your mileage may vary. Dave
     
    olscrounger likes this.
  10. Fact # 1 TH 350's leak. Fact #2 TH350's leak..Put a new "o"ring on the fill tube, A new seal on the shift arm, and new seals on the speedometer gear. That might do it.
     
    reagen likes this.
  11. 29moonshine
    Joined: Dec 30, 2006
    Posts: 1,292

    29moonshine
    Member

    more than likley the filler tube. make sure you have the right seal on the tube. some take a o ring some take a hat if you use the wrong one when the converter drains down it will fill the pan over thr seal and it will leak[ don't ask me how i know
     
  12. 57tailgater
    Joined: Nov 22, 2008
    Posts: 661

    57tailgater
    Member
    from Georgia

    My brother in law has a '40 Ford coupe with one in it and it leaks around the shift lever shaft. But then again it isn't fired up or driven a lot ️ so I assume too the torque converter drains putting the fluid level higher than intended. Maybe a larger tranny pan with a lowered pick-up but using the original fluid amount would work?
     
  13. squirrel
    Joined: Sep 23, 2004
    Posts: 45,695

    squirrel
    Member

    there are several old threads on this problem. The gist of it is that as they said, the converter drains back into the pan, and the following places are likely to leak: (probably a few more I forgot)

    dipstick tube
    shifter shaft seal
    kickdown cable or seal
    speedo gear, sleeve, seal, O ring
    rear seal
    pan gasket
    governor cover
    pump O ring, gasket, bolt washers

    and a few more places can leak while it's running, such as the front seal, and the accumulator cover.
     
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  14. TTTT8
    Joined: Jun 2, 2011
    Posts: 61

    TTTT8
    Member

    Many years ago I had a T-bucket with a rebuilt 350 trans. Same condition you described. I tried replacing the cheesy chrome oil pan with a factory unit, put new seals in the shifter linkage, new O-ring on the Lokar filler tube, all with no success. If it sat a few weeks it leaked. One day I was cleaning the car and happened to look down between the trans tunnel and the tranny and saw a little 1/4 plug - like a tiny freeze plug. It was full of fluid. It was up kinda high on the RH side of the tranny case and pointed up at sort of a 45 degree angle. Anyway, the plug cupped end was full of fluid. Cleaned it out with carb cleaner and let the car sit. Sure as hell a couple weeks later it was full again. Cleaned it again and it looked like the plug had been installed at a bit of an angle and was not seated well. So I just filled it with some sealant, temporarily put tape over the sealant so it would not run out, and checked it a couple days later. That trans never leaked again. I assume the plugged hole must have been a port for factory machining or something, but what I did sure seemed to fix it. Just sayin....
     
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  15. First item, I incorrectly said filler tube. I meant to say the TB cable. But we have fixed it twice?, maybe it isn't. The list Squirell listed s where I'll start, also the small plug that TTTT8 mentioned. I'll find it, when I do I'll report back here. It will be 3-4 wks. or so.
     
    hotrodharry2 likes this.
  16. Man I hope some of these tips work . I've had two of my tri-5 Chevys with same problem , now just finishing up my 36 with 283/350 same story . The problem seams random . Looks like I'm not alone .
     
  17. Well, I haven't had time to ck it out yet. :( BUT, I have temporarily solved the mess of oil on the floor problem. :) It is a washing machine catch all pan. :rolleyes: Works right nice. In fact I bought three. I'm not taking any more chances. NO more mess next winter.
     

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    Last edited: Apr 30, 2016
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  18. hotrodharry2
    Joined: Nov 19, 2008
    Posts: 627

    hotrodharry2
    ALLIANCE MEMBER

    I've had many 350's in hot rods, daily drivers most all have had this problem, rebuilt or used. Just doesn't seem to matter. I have to agree with many others here (Squirrel, Robert Jam, typo 41 & others) There are a couple of great suggestions here as well such as a catch pan, or sucking about 1 quart out of the trans out while your cars are in storage. This is what I love about hamb, everyone (maybe not quite everyone), share their life's lessons to help us who haven't figured it out yet. Good Luck! I have a new strategy.
     
  19. olscrounger
    Joined: Feb 23, 2008
    Posts: 3,802

    olscrounger
    ALLIANCE MEMBER

    I have used many of these over the years as well. We have gotten at least 10 over the years from the same builder complete with flexplate and converter and put in 40's. Have two here now-they only leak a few drops now and then. They are very easy to overfill and after market dip sticks seem inaccurate. The builder told me to put in so much fluid and see if it functions (9 qts)-did not move-added 1 1/2 qts and worked fine. Have you ever looked/asked how much fluid they take? Get answers from 8 1/2 to 11 1/2 qts. I know volume changes due to cooler type etc.-mine have two. The only leaks I have encountered are at the shift arm (easy fix-KB has a tool)) and the speedo bullet. I have not had the drain back problem with these but did with a 700R and all powerglides I had--must be lucky I guess. Have fixed several for friends that leaked badly at shift arm. There is some sort of a one way valve that goes in one of the lines that is supposed to prevent the drainback issue but I have never tried one.
     
    Last edited: Apr 30, 2016
  20. rfraze
    Joined: May 23, 2012
    Posts: 2,003

    rfraze
    Member

    During discussions about leaking Glides, several people have suggested that there is a converter or pump seal which can allow that drainback. Is that correct? Which seal is it, that if bad, would allow that?
     
  21. rfraze
    Joined: May 23, 2012
    Posts: 2,003

    rfraze
    Member

  22. squirrel
    Joined: Sep 23, 2004
    Posts: 45,695

    squirrel
    Member

    Maybe the sealing ring on the input shaft?
     
  23. rfraze
    Joined: May 23, 2012
    Posts: 2,003

    rfraze
    Member

    Thanks Jim. Congrats on HR.
     
  24. elba
    Joined: Feb 9, 2013
    Posts: 612

    elba
    Member

    If the pump bushing is good and snug against the torque converter it will not leak.
     

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