Taguid

I have been having trouble with a leak from the diff. I just drove out both seals and put new o-rings also. If you were wondering, yes I lubricated the seals and shafts before carefully reinstalling. It has been leaking more ever since I started using Mobil 1 Synthetic 75-90 LS. It now leaks worse than before. Has anyone experienced this phenomenon? I also made sure the seals were pressed in evenly. I am wondering about the quality of the new seals from Porsche. Does anyone know if Elring makes the seal replacements for 928-332-215-02? Thanks

soontobered84

I had to replace the diff on my GTS and replaced the seals and O rings. I also use Mobil 1 75-90 LS. and I have had no problems whatever with leakage.

Taguid

Good to know! I can't understand why mine leaks as badly as it does. After Interstate driving I have it drizzling off the exhaust and gas tank.

928Myles

Could the breather system be blocked? (Not sure if it has one)

Taguid

That crossed my mind but I don't know of an easy way to test.

soontobered84

There's a vent cap on the top middle of the differential.

Taguid

I have tracked the leak down to the top vent. Does anyone have experience with changing the vent out? I see in PET that it is a separate part number. I also know that the splash plate for the vent is off a few mm versus what it shows in the WSM. I think I'll try adjusting that first before removing the transaxle again.

skpyle

Hello Taguid,

I don't have any experiences with the leaking vent, but I have some photos from where I have disassembled the differential housing from the A28.07 automatic in my Red Witch. Should be very similar to what you have:




Round black plastic vent on top of the differential casing. There is nothing to the vent. It is just at little plastic cap that pushes in. There is no check valve or baffle.






Note the slot in the top of the back face of the differential casing. That slot is an open chamber that the vent on top goes to. This chamber acts as a baffle, allowing air in and out, but keeping raw gear oil away from the vent.






Better photo showing the baffle chamber cast into the top of the differential casing.





Note the black sheetmetal baffle clipped to the inside top of the differential cover. That baffle works to keep raw gear oil out of the opening for the baffle chamber cast into the differential casing that the vent works from. I believe the sheetmetal baffle deflects oil spray of the turning ring gear from getting to the baffle chamber.

Taguid

Thanks Seth. I just can’t understand why so much spews from the vent. The way I tracked down where it was coming from was to add UV dye to the oil so I could be sure exactly where is was coming from.

soontobered84

Is your differential overfilled?

Taguid

I don't think so is is just to the bottom of the fill plug.

Mads

Taguid. Did you find a solution? i have the same issue. Just went on a 2000km roadtrip, and i got oil loss from the diff. Also on the rear bumper.

Mads

Taguid

I thought I had posted that I had resolved my issue but I apparently did not. Anyway, it was the vent baffle that was too low on the cover. I pushed it back up along with adding a little dreibond to the vent opening because it was splashing out of the vent. I hope this helps. Al least all of my other seals should last another 30 years.

Mads

Thanks for the update. so you had to raise it a little. Not push it down?

Mads

Taguid

Yes, mine was cocked downward to the right so I pushed it up as high as I could. See pic