I have a 2018 ft4 John Deere 850k i wonder if an Trimble CB430 could work on this machine or it has to be an CB460
Sorry for being late, but I think you will have to go with the 460.
From my understanding I got a D6n that runs a cb430 with gcs900 same system as my 750 with a 460 id try it and run diagnostics if it works it would save you about 10k on a new monitor