Guys, I think we found the issue with my X5... checking with a scanner displaying real time data, we found out that the trans oil temp was getting too high very easily, overpassing 130 C.
Then we did a visual inspection of all the components of the cooling system for the transmission and, believe it or not, the last owner didn't change a faulty trans heat exchanger, but instead, he asked for a "temporary" solution in order to not spend some bucks in a new one. So, his "mechanic" (very insulting name for someone who did such a crappy work), replaced the lines and put a 2 meter copper tube and he trow it into the bumper.

How did we find that out? Well, I removed the front bumper to change a PDC sensor and voila! Crappy work all over the place.

I was so angry about it, I can't believe someone can be like that with these cars... or any car. I have never done something like that, not even with my first car (a nissan 200SX 1996)

AAaaaargh! I hope that with a real oem heat exchanger I can keep the oil trans as it should and that no real damage is inside... fingers crossed...

I just wanted to let you guys know... I'm so pissed off!

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BMW X5 2002 4.4i V8 - What a headache!!!
BMW X5 2019 XLine 3.0D - Loving it