Airport extending network drops connection a lot.

I have an interesting network setup. I have two ISPs one from cable and one from Clear 4G(backup). These are both running into a load balence router. one connection is directly from the cable modem and the other is where my parblem begins:

The 4G modem generates a wifi signal, I then pick that signal up with an airport express. The Airport express is then wired into the load balencing router. The 4G ISP is used only as backup and more or less never gets used. When the 4G backup side is being used, I don't believe this problem exists, but I am not sure.

Every 10ish minutes the connection between the airport express and the 4G modem is dropped for approximately 30ish seconds. It doesn't really effect me becuase this is a backup ISP, but I would HATE to to jump to the back up ISP and it be a) in the middle of its 30 second reconnect or b) drop evry 10 minutes.

Any ideas? Thanks

-Brad