1. swing69

    swing69 fightin' socialism

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    My last 904 pan gasket leaked all the time.....constant dripping from the edges. Reseal it 2 times, same result.
    Now I installed a newly rebuilt 904. I figured that the tech installed the pan gasket, so all should be good. Installed it, and yup, it leaks around the edges of the pan :(

    So now I need to remove the pan and regasket it. I've been using the rubberized cork, not the $0.99 cent rubber strip one. I remember there used to be a thicker o-ring type gasket, but I can't find a part number. anyone have it or advice on how to seal the pig? thanks
     
  2. CFD244

    CFD244 FABO Gold Member FABO Gold Member

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    I had a similar problem on a 727.....Changed out the gasket a couple of times with no avail. Finally had enough and took the tranny shop to do the gasket. They changed it and it leaked, put anew pan on and it leaked, changed the shifter seal and it leaked. As it turns out there was slight wear (barely noticeable) in the shaft that comes up through the seal. They changed that, and problem solved. Just my experience. Good luck.
     
  3. Tooljunkie

    Tooljunkie King of cobble/master of the broken bolt FABO Gold Member

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    I use the paper/felt type gaskets. ATP is the brand name. Glue gasket to pan and a nut driver to install it.
    Fwd cars, i have been using silicone and no gasket for years.

    as mentioned, it may not be the pan gasket. Wash, and run it while observing for leaks. Atf gets very thin when its hot,and will wick all the way around the pan if the shift seal is leaking.
     
  4. YY1

    YY1 Well-Known Member

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    Get a $30 silicone gasket.

    I've posted the link before.

    Reusable as well.
     
  5. Snake

    Snake Mopar Nut

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    i just went threw the same problim, get a new pan off a 92 jeep trust me it work for me.
     
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    • toolmanmike

      toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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      Exactly. It probably has a bit more capacity as well.

      If it leaks (again) in the same spot, 99% of the time it's the pan causing the problem. If you think about it the transmission case probably won't be warped. I always lay the pan on something flat and tap the rail and bolt holes flat. Here's a replacement pan. It is deeper than the stock pan and you can use a filter extension or not. It also has a drain plug which is real handy when you want to drain to change the filter or adjust the bands. It works the same either way. Here's a thread with some part numbers posted.
      Deep 904 transmission pan?

      transmission pan.jpg
       
    • toolmanmike

      toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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      Here's one for $12 and change from Rockauto. I just looked up one for a 96 Dakota. (which I own 2 of) It's a direct replacement for a stock pan as you can see at the end of the description.
      More Information for ULTRA-POWER 265839 upload_2021-4-8_8-10-40.png
       
    • diymirage

      diymirage HP@idle > hondaHP@redline

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      so your old transmission leaked at the very bottom
      now a newly rebuild one also leaks at the very bottom

      what are the odds something else is leaking and you're simply noticing it on the bottom?

      the reason i ask is because i struggled with a leaking oil filter adapter for ages
      only to find out it was actually a leaking rear main seal, and the oil got slung up by the torque converter unto the oilfilter
       
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      • '68cuda416

        '68cuda416 Well-Known Member

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        A 12 dollar pan???? Some of guys make me shake my head.......first off buy a real pan like one from A&A that is heavy cast aluminum and has a very thick flange. Second of all I have been down this road before and have tried all the gaskets, all the secret forum tricks and finally I came upon something that works 100%..........you use a real pan for starters and not some cheap, flimsy metal pan,you use the reuseable mopar plastic/rubber bonded gasket and you coat both sides of it with aviation form-a-gasket and let it set for a few minutes and BOOM no more leaks of any kind!!!!
         
      • toolmanmike

        toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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        Buy the other one I pictured above then. It's $42. Yes the aluminum pans are great but can be overkill for a stock type application.
        Dorman 265-839 Dorman Transmission Pans | Summit Racing
         
      • YY1

        YY1 Well-Known Member

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        • Thanks! Thanks! x 1
        • toolmanmike

          toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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        • rustycowll69

          rustycowll69 Well-Known Member

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          one thing to watch out for, especially when using cast pans, and/or the thick composite plastic reusable gasket is bolt length. Too short, and you may not have enough thread engagement so that you may strip out threads in trans case when torquing fasteners. Too long and the bolts may bottom out in bottom of hole before needed clamping force is reached.
           
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          • CudaFactHackJob

            CudaFactHackJob FABO Gold Member FABO Gold Member

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            That Jeep pan is great; lots thicker steel. But I can take any old beat up bent up twisted pan and get it to seal with NO SEALER and a $3.50 gasket. DUPRENE fiber in black or reddish brown; but the trick is to not try to just straighten the pan rail. You have to pound on the holes so you pre-stress the area between the holes when you torque it down. Check the pan by laying it on a flat surface and maybe use a flashlight to check the rail. You don't want the hole areas touching the flat surface. The external rail should be straight, but the area adjacent to the hole by about 1/4" shouldn't contact the flat surface. It will when you tighten the bolts. And I tighten the bolts to the extreme; the gasket won't split. An added precaution against gasket splitting is to sand the rail in the direction of the rail; it will help the pan to grip the gasket. Do the case too. I save the rubber and neoprene/cork gaskets for aluminum pans.
             
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