Whenever I try to record live in 4k 24fps (with a FPV monitor via 5.8ghz channel transmitter and reciever) on my Phantom 2 (with gopro gimble) it stalls and does not record.  I can record 2.7k 24fps just fine.  

I know the SD card I have can handle the write speed.  It's a SanDisk - Extreme plus 32GB microSDHC UHS-1 Class U-1 memory card and can write up to 50 mb/s.

Can the Phantom 2 gopro gimble system just not handle 4k footage?

Btw, the GoPro on its own can record in 4k just fine with the same cards and such.

h3-3d gimbal can handle go pro 4 but old h3-3d gimbal is better

That is strange.  Sounds like you've cover all the bases.

Just a couple things/ideas I would try...

Restart the camera by removing the battery.

Try with the GoPro battery fully charged.  Perhaps that recording mode is surpassing available power requirements???

Hope you get it figured out, and please do share when you do.  Good luck!  

You use a Gopro4?
wow....I have no idea with that sorry....
Try to ask Gopro for help?
And Happy Thanksgiving

Where are you located? I noticed you're recording at 24fps. Make sure both the GoPro and your FPV receiver are both on NTSC or PAL.
I had the same problem and switched my BlackPearl monitor to NTSC and all works well at 4k and 30fps.

I live in Florida.  And I'm not certain that NTSC or PAL is the problem.  I'll double check that they're on the same, but the issue isn't that I can't see it played on my monitor.  The issue is that it stops recording completely and just freezes.  I have to turn the camera off (by taking the battery out) in order to get it to reset.

This issue was resolved in what I believe to be a firmware update for my go pro and gimble.