Warn hubs

[Tiponinn]

I have a 04 F350 with warn hubs. The right side will not lock. I took the cap off and if I push in the gear by hand the hub locks and the axle spins. Put the cap on in the locked position and it will not stay locked. It pops out and you hear a clicking noise. Turn it to free and all is quiet. Turn it to lock and the same happens. I also just had upper and lower ball joints done on this side. Not sure if that has anything to do with it. It was working the last time I used it a few months ago. Any help would be great, Thanks