I don't think "transmission" would work in a business context in French.

Yo can say : "Ce sont les connaissances transmises par son mentor".

Les connaissances léguées par son mentor.

pass down is a phrasal verb. And even if used as a noun, it would not be written without the space. That here's the passdown from the Boss is NOT the same meaning as the phrasal verb. It is also non-standard. He passed down the instructions to us. = nous a fait parvenir

You seem to always post terms with two completely different meanings. I just wonder if you are aware of that. What the boss passed down to his underlings is not the same as what grandparents pass down to their grandchildren. The boss passing something down goes to a hierarchy in the workplace whereas the grandfather idea is about generations. And you never interact with questions or comments to you...

Of course I understand that terms have literal and figurative meanings. The OP often fails to give examples of both. That is the case here. Responding to requests for more information is not nitpicking. [correction: often post terms with two different meanings]

@Lambie Thanks for providing an answer!

@Lambie I hear you but providing an answer in the comments is not a request for more information. Nor is asking the poster to agree with your comments.

@guillaume31 Bob met his boss Alice. Alice told him X and Y (e.g. X = "We'll hire 2 new employees this year" and Y="Our GPU budget will double in Q2"). Bob then met the team he manages. Bob tells them: "Here's the passdown from Alice: X and Y".

The passdown there in: Alice told him X and Y is merely: Voilà les infos qu'elle (le chef) nous a fait parvenir. But that use of passdown is not in the dictionary and is not standard English. It's invented by the speaker.

@Lambie There are enough earlier occurrences of passdown for it to have been invented by the speaker here. Here for example. Words need not to be listed in "the dictionary" to exist.

@jlliagre Yes, I said that, didn't I? English nouns are often verbed and verbs are often made into nouns. That said, my explanations are 100% correct. It would be good if the OP acknowledged this type of fact (not a standard "term"). And if you cite text, provide an actual link.

Pass down is a fundamental concept taught to all branches of the military starting the first day of boot camp or officer candidate school. General Order Six states the following: To receive, obey and pass on to the sentry who relieves me all orders from the Commanding Officer, Command Duty Officer, Officer of the Deck and Officers and Petty Officers of the Watch only. navalsafetycommand.navy.mil/Portals/100/…

Yours and this one I found are the same idea as the semantic feature I mentioned> to pass information or instructions or tasks to someone. Nothing I said in my answer goes against this usage and it is non-standard. And who said non-standard is bad? Not me.

@Lambie I was referring to the compound spelling (passdown) which you insist to reject. I don't see the point of enforcing the separate spelling.