Hello @oldturkey03 ! first of all thanks for your answer
I wasn't finding the steering pump because I didn't imagine it was attached to the engine body, but now I found it.
If it helps anyone else, I will explain why I was looking for that part.
Steering wheel is getting harder to turn and it makes more and more noise every time...
Then I found out the 2.5 tdi 130hp 2005 VW transporter T5 with A/C (not climate control) and manual transmission, has a common problem.
Eventually, in this exact engine model (also in 2.5 tdi VW Touareg) when steering pump gets old or damaged, it can communicate engine oil with hydraulic steering oil system.
Fortunately, it seems it only happens this way, not viceversa (otherwise my engine would be dead)
I could check steering liquid was totally black, not green/brown so that confirmed the suspect...
So I need to replace the steering pump which is damaged because has been working with dirty fluids, then clean the steering hydraulic ducts and good to go!
Thank you again for your support :)