Oil Distribution

WARNING: This page is about a different car, the 2023 Audi Q8. However, it is still accessible from the selected car via links, so may be relevant.

There are two different versions regarding the lubrication of the final drive and the self-locking center differential.

Fig 1: Protective Pipe, Transfer Case And Front Final Drive
Courtesy of AUDI
For transmissions with a shared oil system, the oil chambers in the front final drive -3- and in the transfer case -1- are joined via the protective pipe -2-.
The side shaft runs in gear oil in the protective pipe -2-.
Transmissions with a single oil system do not have an oil overflow hole -arrow-.

Courtesy of AUDI
A transmission with separate oil system can be identified by the oil overflow hole -arrow-.

Courtesy of AUDI
On transmissions with separated oil system the protective pipe is free of oil, the transmission as well as the front final drive are sealed with a gasket to the side shaft.
Always pay attention to the different control and filling specifications.
Refer to GEAR OIL, DRAINING AND FILLING