tranny fluid leaking into differential and out the driveaxle

[markclaire]

Hi all,

I have a 92 Legacy L FWD that has developed a pretty decent transmission fluid leak. But inspection reveals that the leak is coming from where the left front driveaxle fits into the differential.

It started when I noticed small puddles of what looked like an oil/tranny fluid mix. I noticed that the differential was overfull, so I drained it and filled it with the proper gear oil, also filling the transmission fluid to full at the same time.

no real leaking for about two weeks until we drove from seattle to portland this past weekend. Upon arrival, the tranny fluid was about a quart down, the differential was overfull again with tranny fluid in the mix and tranny fluid poured out of the driveaxle until the car cooled down. Given the rate that it was dumping when we stopped, there is no way that the leak was significant while we were driving at freeway speeds, or else it would have been completly empty.


So - I'm assuming the diagnosis is some sort of seal and that leak has to do with some sort of pressurization, but don't know. I would really appreciate any suggestions and rough estimates on for what it might take to fix this? I have dropped manual tranny's before to replace clutches, but have never messed with automatic transmissions, so don't know if that is alot more involved, but may have to do it myself if the cost is over a grand...

Also, do you think I'll need to replace the differential as well? The car shifts/drives well even with the tranny fluid in the differential, but I don't know what sort of long term damage having fluid of the wrong viscosity can have.


Thanks so much for any advice you can give.

Mark

[Legacy777]

It sounds like the output shaft seal between the transmission and differential is leaking.

Pretty much only way to fix it is to drop the tranny and pull the differential off the transmission.

[markclaire]

Thanks. I probablly have the skills to pull the transmission off, but is the seperation of the transmission/differential and replacing these seals a reasonable task for a motivated amateur? Are there any particular write ups beyond my Haynes manual that you can recommend that detail the process for a FWD automatic legacy?

Thanks again,

Mark

[Legacy777]

Having not done anything like that myself....I really don't know.

You could probably separate the trans & diff, however I'm not sure if the transmission needs to be disassembled to get the pinion shaft out so you can replace the seal.

[Project_Legacy]

if this is the seal that i am thinking about, i just had this replaced on my 91 fwd legacy. i dont mess with transmissions at all as i dont know anything about them, so i just got it done at a shop. cost about a good $600?

there was a new updated gasket for it, so be sure to pick that one up. i think the subaru shop said the old one was made out of some really weak stuff.