2014 sd4. 50,000 miles.

Changed diff oil. Got 500ml out, about 650 back in. 🤔 moment!!

Drained oil was brown and had micro bubbles.

As I had bought 2.5 litres for the price of 1, so I ran for few miles and replaced again, not sure how much old was left behind diluted. Drained about 650 ml that time.

However, the new oil also had micro bubbles. Is this normal?

Bearing in mind the old fluid had bubbles and was actually low, so overfill wasn’t the reason..

I levelled with a spirit level and allowed to drain excess for a long time.

Answering my own question….

Normal! Nice video.

the tiny bubbles take ages to clear Jules