Audi A8 transmission problems
 

Hi, my car is a 1998 A8 Quattro Sport 4.2.
A few minutes after start up, there is like a droning, clacking noise coming from the transmission area. If i rev it, it sounds like a whizzing noise, like a cooked bearing.
My question is, i suspect the pump bearing is failing, so apart from changing the filter and fluid, is there anything else i can do? Is it easy to change the pump? Is my transmission likely to fail very soon?
Its done about 95k miles btw.
Cheers.

I would have the fluid and filter changed on the transmission ASAP before anything else. See if that fixes the issues, if not, you may need a new trans. Its common for D2 transmissions to go out.

Thanks for the reply.
I've ordered a new filter, gaskets from Audi.
According to elsawin, i can only change 4 litres out of 9.5 litre capacity when i drop the sump. Is this the case?
Also i had a good look under it yesterday, it does appear that it has been losing fluid. The leak seems to be coming from where the main transmission loom leaves the box, is this common? and is there any easy fixes? has anyone used any stop leak products in the transmission?
cheers again.

You may be leaking from the torque conveter seal, and yes this is common. People usually let it go on like that and fry the trans. If this is the case, then removal of the trans is necessary. I would double check and verify that it really is tranny fluid and not oil though, you could be leaking from the valve cover gaskets on the back of the heads too. As for the fluid, yes you can only change out about 4-5 liters, but thats enough.

Thanks.
I have changed the oil and filter, and the noise has stopped.
But there is still a bad leak, i'm not sure if its engine or gearbox oil.
There is a wiring connector at the rear of the subframe, it has a large rubber bellows covering it, the oil is running down this loom and gathering on the bellows, it is then dripping down onto the subframe.
The valve cover and hall sender appear to be dry, is there anything else on the rear of the head that could leak? or is it likely to be the crank rear oil seal or torque converter seal?

Well check the oil level, is it low? You either have to use a small mechanics mirror to see a leak at the back of the head, or you can feel around behind there and see if its wet. If you feel any oil back there thats where its coming from.

Now when you say a bad leak, do you mean fluid is pouring out, or is it like drip drip drip? If its a fast leak its most likely tranny fluid. Since you just changed the trans fluid the fluid would most likely be clean as well.

Thanks for the response.
I've tried using a mechanics mirror, however with the amount of pipes behind the head, i just can't see anything. I'm thinking of removing the throttle body to give me more room?
The leak is dirty, and it is like a drip drip type of leak.
The engine oil doesn't seem to have dropped. However when i checked the auto box oil level, it did need topping up. But that was a few days after it had been changed, and it had done about 200 miles.
I will check the level again on the transmission.
Are there any sensors on the back of the v8 block or head?
Cheers.

If its dripping that fast its most likely a transmission leak. Torque conveter seal most likely.
There are various sensors behind the motor, but none you need to worry about now that i know its a trans leak.

Are there any additives that are ok to use to stop the leak?
There does seem to be a lot of oil higher up on the head, but it is hard to see because all the piping. I will probably remove the throttle body at some point so i can get a better look. Can the auto trans fluid leak that high up?
The leak isn't fast as i can actually see it dripping out, but if i go for say a 5-10 mile drive, there is oil on the subframe again. It is coming off the undertray and ending up on the n/s cat converter. The converter actually smokes with the amount of oil on it! Is this likely to cook the converter?
Can you tell me what sensors are on the back off the head? i'd still like to check them out.
If the seal had gone on the torque converter, is just a new seal needed or will i need to change the torque converter?
Cheers.

i had the exact same problem when i first got my car, but luckily it was a new tranny that had a warranty. they'd just accidentally rolled an internal seal. when you have a tranny specialist look at the converter seal, they may find a leak that is your culprit like Auditech said, but if you get a shop to fix that, you might as well have them re-check the internal seals as well in case that's an additional issue. The seal on the tranny had been redone twice before I picked up the car (the original shop kept missing the internal seal as the culprit or rolling it somehow)... then I got to a tranny shop down here where i live, that was in their network. that shop re-evaluated everything inside out and i haven't had problems with it since (knock on wood, fingers crossed, God willing, etc lol).