Alex2.7T

I noticed that my car is leaking ATF when parked on level ground , I lifted car and noticed that the leak is between the transmission and rear driveshaft cover, how difficult is that to fix ? Or what could the issue be? It was all good before I replaced transmission pan gasket, filter and ATF change....

SloopJohnB@mac.com

If it wasn't leaking before you changed the pan gasket it shouldn't leak after. Of course it could be coincidence, but look for horses, not zebras.

Before you go to the aggro of pulling the tailshaft housing I would redo the transmission pan gasket. Carefully save the drained transmission fluid in a CLEAN container. If it's clear fluid it can be reused.

When you refill the trans, put a UV-florescent dye in about halfway filling or put the dye with the fluid in the clean container before you start refilling. You should be able to check whether the leak is really coming from the trans pan gasket or not.

You could also recheck the ATF level and put some dye in the trans before you drop and replace the trans pan gasket. That way you only have to go through the ATF level setting procedure twice to demonstrate the pan gasket is leaking but who knows? You might get lucky and indeed it is that tailshaft housing gasket. It happens, but I venture to say the pan gasket and ATF flush and filter replacement had nothing to do with the tailshaft housing gasket leak.

Prospeeder

You sure its ATF? The rear housing only leaks gear oil. Since its the transfer case. If so you will have to undo the clamps on the converters, move they aside, and remove the driveshaft, push it aside, and undo the allen bolt in the center of the driveshaft flange remove, and replace the seal. Then be sure to top off the transfer case with synthetic 80-90 gear oil.

Alex2.7T

I took a whole bunch of pictures from underneath the car, its leaking between the "cats", it looked to me like trans atf but probably not, but it looks like it, maybe the one used in the driveshaft looks like atf, I cant really tell the difference

Alex2.7T

after a closer look to pictures apparently its not the transmission pan(yellow circle), since oil is leaking way behind it, between the cats(red circle). how difficult will this be to fix? any advise will be appreciated.

Prospeeder

Yea thats gear oil. Its the rear seal like i said.

Alex2.7T

Is that an easy seal to replace?
It will be my first time working on that part of car.. any do's and don'ts will be greatly appreciated?

Airbag

audi has an upgraded part for that spot. but I think the original leak prone seal is still available.

its a pain in the *** but not difficult. need to pull out exhaust, take off heat shield, drop axle ( cv joint ) then replace seal.

Prospeeder

Loosen and slide back the exhaust clamps, unbolt the driveshaft, move aside, and remove the bolt in the center of the flange. Replace the seal. The "new" style seal need a different flange. Just get the original seal. it lasted this long, it will last till the car dies. be sure to top off the transfer case with synthetic gear oil.

Alex2.7T

Thanks Prospeeder and Airbag, it sounds easy to replace, I will work on it pretty soon, hope everything goes well...