why does my transmission leak?

[novaderrik]

the front seal in my trans has a really weird leak. it never leaks at all when it's running, but once it's shut off, it might leak a little, a lot, or not at all. i haven't even started the car for about 2 weeks, but it started leaking yesterday and now there is a huge slick under the car. 2 days ago, i swept under the car and it was bone dry.
it was about 100 degrees in my garage yesterday, maybe that had something to do with it? but it has done this before- even in the dead of winter. i usually keep a drain pan under it, but since it didn't leak at all for the entire month it was my daily driver, i didn't bother.
the vent is open, and it is definitely not over filled. in fact, it will leak enough just sitting that it will probably need 2-3 quarts just to get the damn car to move again.
i'm thinking that it is somehow pulling up thru the filter and into the pump, where it then goes out the seal. it only stops leaking when the fluid level is too low in the pan to cover the filter. but it really makes no sense why it would do this, and it's really annoying.

 

[novaderrik]

no one wants to touch this one, eh?

 

[pdzz]

I've seen transmissions leak out of the slip yoke after sitting, small hole in the yoke itself. The converter can drain back over filling the pan which is what causes the leak. But, I've never seen it come out the front seal. Is the seal original? Can you tell if it's coming from the torque converter seal, or the o-ring around the pump? Sorry, not much help.. Phil.

 

[novaderrik]

seal was new in April of '09- has maybe 2000 miles on it.
it sat from last July or so until June of this year without leaking. then i drove it for about a thousand miles this summer, and it didn't leak the whole time.
after it weas parked for a couple of weeks, it started leaking one day, which led to a hug red slick under the car.
it is definitely coming from the front seal- i can see the trail of fluid with a flashlight.
it doesn't leak at all when it's running, and might not leak for days after shutting it down. but once it starts dripping, it sucks the pan dry to the point where no fluid shows on the dipstick with the engine off. it;s like when you siphon gas out of a car- it keeps flowing until the end of the hose is uncovered.

 

[SSedan64]

That's a weird one. There're several reasons it can leak there. Pump seal, Bushing worn, Bushing walking forward cutting Seal, Drain Back drilled too far, Converter snout/neck cracked. Most leak while running also. Are you sure the Trans vent is clear? Seeing as it sat for a while those Dirt Dabbers love to plug things up.

 

[novaderrik]

vent is clear.