I know this subject has been beat to death. Have read and read with search and cant find a solution. 2 wheel works fine. Good vacuum to both wheels. Solenoid is working. Cuts off vacuum when shifting to 4x4, Check valves are good. Lights come on dash and even checked the transfer motor. You can hear and feel it locking in. Passenger side is meshing but drivers side is not all the way. Jacked it up and can turn the wheel backwards and it will mesh and turn the axle but turn it forward and it does the clicking deal. I pulled the IWE off and it looks fine. Splines were good on both axle and hub. Changed the vacuum hub and still the same. Made sure it was locking before i tightened up the axle nut. Locks fine and tight with the three hub bolts loosened some but not after you snug them down. Axle is good. Hub bearing good, upper and lower ball joint good. Seems to be binding but cant find where. Guy before me said he replaced them both before but said he pulled the axle on drivers side to get more clearance. I didnt have to. Looks like it is mounted back fine. Does the axle have to mount 1 way?? Has me stumped.

 

All these views and no ideas at all?

 

Both IWEs have to totally engage, or else no power is transmitted to ground.