|
I've bought my car second hand. As soon as I brought it home I've replaced all the fluids - at that time my Z4M had a mileage of about 29,000 miles.
The differential oil came out very clean, but I was horrified by the look of the gearbox oil. It was the darkest used gearbox oil I've ever seen pouring out of a manual transmission. Unfortunately, there's no oil analysis service in my area, so I've simply replaced it with original BMW MTF-LT-2.
Based on my experience, I'd say analyze the transmission oil rather than differential, if you have to choose.
But then, every car may be different...
|