Jack the car up, spray all of this with degreaser and brake cleaner. Wash it off. Go from there. Will be alot easier to pinpoint versus how it is now is like finding glass in the ice bin.

If it doesnt seem like oil the other two things is power steering fluid or diff fluid, I believe certain X5;s use ch11 and some use ATF. Atf will be on the redder side. CH11 will be like a darker brown/greenish color.

Diff fluid if never changed will be black as hell and diff consistency, if more recently changed, a goldish color/light brown.

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2006 X5 4.8is Fully Loaded