transmission Question !!!!!!

[Monster]

  My 727 in my cuda leaks fluid out the o ring seal where the spedo gear goes.  not the nut.  this all started when i went from 2.75 gears to 4.11 gears.   one person mentioned the vent being plugged and another mentioned the modulator rod needing adjusted.   also when i changed the spedo gear ( after the problem already was going on) fluid was built up to where it poured out when i removed the gear.  lots of fluid.   over a qt i think.   please help.  its starting to turn to winter and i need to drive my toy     also   what is the stock compression for a 1967 440    i run 110  in the 1/4 now but checked the comp on the drivers side and it was  115, 75, 70, 85.  not so good huh.   

[Moparal]

The vent tube is behind the converter, I doubt it is plugged up. If you had the car on an angle and on the stands, then fluid running out like that is normal since the fluid goes up into the dipstick a bit as well. Sound like you need to replace the big o ring to me on the speedo trans housing. And your compression sounds like it sucks huh? What did the other side run? Bet you dont have hardend seats on those old 40 yr old 915 heads. May be time to freshen up the top end so you can blow the rings out of it   When you drag race an engine, you shouldn't count on driving it as a everyday user and all through the winter without the standard up keep that is required. 410's in the winter will hurt to. Maybe buy a beater car and freshen up your stuff is a better idea you might consider....

[FJ5_440]

Tactransman will certainly do a better job of helping you if the transmission is actually building up too much pressure, but it is pretty normal for a tranny to lose fluid out of the speedo hole if the vehicle is level.

Like Al said, you might want to change the small seal in the housing that the speedometer gear goes into and the large O-ring where the housing seats into the transmission case.  The large O-ring should be fairly easy to get at any local transmission shop, but they may not have the seal for the housing to speedometer gear shaft.  
Tactransman may have them available (super nice guy and member here), or they are both available online:
http://www.transmissioncenter.org/speedometer_gears_for_dodge_and_jeep.htm

[Monster]

when this first happened i ordered the large o ring.  when i removed the housing to replace it the one in there was covered in black gasket.   i replaced it with the correct o ring.   it blew fluid out anyway.   i replaced it with a thicker o ring and it did it again.   i replaced it finally with a thicker o ring and black gasket goo and on my way out of town it blew out again.    could the modulator rod from the carb be out of adjustment now with the extreem change in gearing.  it all started with the gear change ?

[tactransman]

The replacement "O" ring is orange instead of the original black one. If you are not careful on the reinstall,you will cut a chunk out of the new one when reinstalling,the adapter housing could be bad too,did you look it over real good?

If the vent is plugged up,it could make it worse,it would probably push the dip stick up first though.Does the fluid run down the funnel normal when you added fluid or does it take a while and kind of "belch up" in the funnel when it goes down?

The kick down rod has nothing to do with the "case" pressure which is all we are talking about here.

This is a good pic of the internal seal and small clip that holds it.

[Monster]

it leaks out the large o ring.  i even  (last straw) used black gasket on the housing, then on with the orange o ring, more black gasket then installed the housing  let it sit for a week then tightened the retainer for a tight gasket fir.  it worked around town for about 15 min.  then left town and it blew out again.  my dip stick is very very tight so it would be hard to pop out.  i will check the vent.  would that build a lot of pressure

[tactransman]

It could ,yes. Here is a pic of the vent.

[71chally416]

As for the compression, 45 lbs of variation is bad. Might be time for some rings. 

[FJ5_440]

If it were me, I would check over the speedo gear housing very well, then replace the O-ring again and drive around with the transmission dipstick out, or in super light..  If there is no more leakage after a decent amount of time, put the dipstick back.  If it blows out the seal-you know for sure it is a pressure issue.  If it leaks with the dipstick out, your sealing surfaces are the issue.

[MyMopar]

I'm with the sealing surfaces being bad.  It could be that there is a nick or gouge in the sealing surface.  You said it was fine before changing the speedo gear for the gear change so I would imagine that somehow the surface is damaged.

[Monster]

actually it went bad after going from 2.75 gears to 4.11   thats when it blew out.   then i have changed the gear while trying to fix the leak.

[Moparal]

In a way, if you wanna go riding. Just pull the dip stick up a bit and let it vent there for the time being.  It still has a bell for the cover on top and wont be blowing sealing. Not a fix, but lets you get around some.

[Monster]

Found the engine compression problem.   exaust valves burned up.   did leak down and it was almost like all the exaust valves were open.  i can turn the engine over by hand easily.  gonna get the edlebrock preformer rpm heads to match my intake and carb and cam.    hey  the good news is i still beat my dads 67 chevelle ss 396 by 2 car lengths with 1/2 compression.  lol