A little help maybe

I just found out that the 4WD Actuator on my front axle took a crap and it won't allow the front axle to lock in when I put my truck into 4WD.

Can anyone out there that has done this already (mechanics etc..) or anyone with any knowledge of this, tell me how to remove the actuator from the front axle to replace it, it's plastic and I'd rather not snap it off trying to pull or unscrew it. Also is there anything I need to be aware of before doing this?

Thanks guys!