Question about the Klaw's resource transfer abilities in career

[Yellowburn10]

So, in my career I have the level 2 R&D, which should give me access to resource transfer, and it does for most things, but for some reason I'm unable to do resource transfer with the Grabbing Unit. I've checked on my sandbox save and I'm able to transfer with the Klaw there, so it's probably not a bug. Do I need to further upgrade my buildings in order for this to happen, or is there something else wrong?

[Gargamel]

Moved to Gameplay Questions. 

[bewing]

To make resource transfer work with klaws you need to unclick the button in the Difficulty options that says "resource transfer obeys crossfeed rules".

[AHHans]

To expand a bit on @bewing's explanation: the Klaw and some other parts (e.g. all the heatshields) do not allow crossfeed or resource transfer through them, they also have a note in the parts description that tells you that. One way to go around it is to change the corresponding difficulty option. Another way - which is more useful for heatshields, but not so much for the Klaw - is to place two fuel ducts that bypass the "offending" part, one duct for each direction. That will then also allow resource transfers. And finally: freshly created fuel from an ISRU unit will be deposited in any applicable fuel tank, regardless of any non-crossfeed parts in between. I use that latter feature for my "universal refueling rover".