Hi,
Here’s the [https://cardiagn.com/bmw-x3-e83-2007-2010-service-repair-manual-wiring-diagrams/|BMW X3 E83 2007-2010 Service Repair Manual + Wiring Diagrams]
Scroll down and click on the ''Transmission'' link to view this section of the repair manual.
It shows where all the seals, gaskets and o-rings are so that once you’ve worked out where the leak is coming from you may know what has gone wrong.
Hopefully a start