Panelhead

I decided today is the day to flush the front differential. Looked it up in my manual, see it is front of the axle. Rough drawing of surrounding 8 mm bolts. Pulled the wheel, released the liner, and cannot see the drain plug. Where I expected it there is a moulded round hole. All the 8 mm I can see hold the axle on. The ride height adjuster may be blocking my view. It is really hard for my XL hands to citing there.
Am I looking in the correct location? The drawing shows it inside the little bolt on cover.
Is this drawing for a different front differential? It is hard to believe it is hidden so well from the wheel well. And all the bolts Round there are 8mm.

Panelhead

A couple pics

Panelhead

This plug is not 8 mm Hex, the inside is smooth. It is the only bolt or plug I see in front of the axle that does not hold the axle in.
This is on the passenger side, US model, in front.

mishar

There is no drain plug on the front differential You must use vacuum pump to suck oil out.

Panelhead

I had my handy Mityvac sitting there ready. But the drawing in my manual does not match the differential.
I know you have flushed yours, which plug did you pull out?
The one the matches the drawing is round inside. Definately a plug also.
The diagram is A39-039. It is definately a different differential from what my car has.

mishar

That's the one. Just it is not round hole. It is rounded hole. It was Alan key before somebody damaged it.

Panelhead

I really looks like that. Must have used an English hex to foot. The 8mm just spins. Guess this is "Lifetime" fluid.
It was easy to it is a plug. Right spot too. Just my manual drawing does not jive with the actual unit. Heard this about other Audi manual drawings.
Wasted half a day removing the wheel, pulling the fender liner, and after not being able to remove, hunt for a correct plug/fill port.
Some upside though. Never used The jack before. At least on the A8, the jack works great. The tool kit in the lid of the trunk did a fine job also. Pulling fender liner was fun, reinstalling was harder.
The UCA's, a good upclose inspection. Looked fine after 12,000 miles. So install must have been fairly correct. Do have about a 1/64" lip on both sides of the rotor. This may work out as 60,000 miles for replacement.

MP4.2+6.0

I can reach the front diff fill plug without any fender liner removal if I go in just right from below and work around the CV axle connection. It is metric allen head. On W12's and S8's with the combined front and mid diff gear oil interconnected system, you can drain it, but it is done (at least by me) by dropping the gear oil cooler. It's actually the mid (Torsen) diff fill plug that defies any normal service efforts...til I modded the support cradle casting with the Makita that is. My C5 4.2 front diff was definitely lifetime fill--no flipping way I could reach the fill plug, which fortunately I realized before I ever pulled the now deleted drain plug.