4wd not locking front axle

[Snakehearts]

Vehicle info 2000 Chevy 1500

 

basically when I press the button to put it into 4wd low or high it does not lock the front axle I have been told my t case is working and my  actuator  Is working fine aswell I was wondering if I whould have to rebuild my front end or not I’ve been told by a couple buddies it’s the inside of the axle it’s self but they chould be wrong 

[davester]

Remove the actuator from the front diff yourself and see if it goes in and out as you switch between 2wd and 4wd.  That'll verify that the actuator is working right.

 

Double check that the TC is also shifting right when you do this by trying to rotate the driveshaft going to the front axle.  In 2wd, you should be able to freely rotate it, and in 4wd, you shouldn't.

 

If everything you test checks out (actuator goes in an out, driveshaft does/doesn't rotate appropriately), then the front diff needs repair.  Most likely, it's either the locking gear or the passenger side axle, as those more commonly fail than the rest of the diff.  You can just unbolt that side of the diff, leaving the main part installed.  If  when you do this, and neither part is broken, then the main diff is pooched, and then I would recommend just finding another used 1500 diff with the same gear ratio and swap that one in.