john deere 310 4×4 stoped working ??

Hi Everybody, :Banghead I have a 2002 JD 319 backhoe, 4x4, it was working fine till the other day, the 4x4 just stoped working, no nose, no banging , grideing, notthing, just stop working, I checked the fuse, and the switch, bothj good, power both sides of the fues, and power to and from the switch, after them two I am lost, and ideas would be grate, Thanks so much for your time.