Last evening I changed the oil on my 2002 Audi A6 3.0 Quattro. I noticed a small oil leak on the belly pan towards the back. Upon further inspection I saw that the part circled in red in the attached picture was saturated with oil. What is the name of this part? Note, this is a photo taken off the internet so ignore the rectangle box.

Thanks,

 

I think that is from the oil breather hose from the VC

 

Isn't that the oil level sensor?

 

Upon further research online I discovered that this part belongs to the 5HP19FLA transmission, as shown in the attached photos. What does this part of the transmission do? And why might this be saturated with oil?

@twopedalwarrior - I checked the oil breather hose and it was slightly caked with oil but not blocked. I cleaned out the caked oil residue. I take it that you were suggesting that the oil leak may be coming from the rear main seal, right?

@ Sheldon - the part is not an oil temperature sensor, which is located on the oil pan.

 

My guess is that you have leaking valve covers which is allowing oil to drip down, and then pushed back by the passing air while you drive. More specifically, your passenger side is leaking the most.

Do you sometimes smell burning oil or if you pop the hood after warming up the engine do you see white smoke coming from behind the engine?

 

@ Nebuchadnezzar -

The thing is that I haven't driven the car now for a week now-it's been sitting in the garage. Therefore there has been no passing air that's would have hypothetically pushed the oil to the back of the belly pan/tranny location.

Also, I never smell burning oil nor do I see white smoke coming from behind the engine.

I moved the car last night and it revealed three drops coming from the same area. Two of the drops actually were about a foot farther aft, which makes me believe it's coming off the transmission. I suppose I can differentiate whether or not this is engine oil or tranny oil by cleaning off the leaking oil, adding dye to the engine oil, running it for 1/2 an hour, and checking for UV light in the new drips.

 

I am going to go with the valve cover, possibly cam seals. IDK if the seals are the same issue as it was for my 2.8L 2001 Avant..

The VCG job is rather easy - I'd start that direction before you start replacing odd ball parts

 

The color of transmission fluid would have a green-ish color to it. So if you are able to get some on your hands and slowly smear it, it should look greenish. If not and it's brown, then it's oil.

There would still be some dripping if the car hasn't been driven for a few days. Cam seals and valve covers make a pretty big mess when they go.

 

its a gear case for the front wheel drive of your quatro
it takes synthetic 70 wt
probably has a bad seal, located behind the axle
I don't know if you can access it by removing the axle, because I am not sure if the shaft from the case can be removed with the transmission in the car or not.

Mine leak too

you can fill it up by removing the front wheel
there is a plug on the side of the case
You'll need a hex bit (allen) and a super long extension possibly a universal swivel
It wasn't hard to get to, there are holes to stick the extension through.
fill it until it pours out the plug
when it stops leaking out....It is full, just cap it off
depending on the leak you should top it off as you feel its needed.
don't run it empty. but don't overfill it either.

10.00 seal
days of aggravation?