1988 K1500 4X4 Front Axle Won't Engage

I have a 1988 K1500 4X4 and the front axle will not engage when shifted into 4 wheel drive. I checked the acuator and it is working but the front axle will not engage.
Can anyone help me with this problem??

I have a 1988 K1500 4X4 and the front axle will not engage when shifted into 4 wheel drive. I checked the acuator and it is working but the front axle will not engage.
Can anyone help me with this problem??
Are you sure the actuator is extended to full length?

I am sure that the actuator is working fine.
I removed the actuator and use a short length of round dowel and pushed on what ever the actuator pushes on and rotated the wheels and the axle will not engage.I pushed as hard as I could and it still would not engage.
Any ideas on how to free up what ever is stuck???????????

What exactly does the actuator actuate????
Could this thing bind up or get stuck in some way???(The part the actuator engages)
I tried to push on whatever the actuator pushes on and the axle would not lock
Any ideas??????????????????????????

The accuator pushes on a shift fork. The shift fork is probably wore out.

So how involved is replacing the shift fork in the front axle???

Pull the housing that the accuator screws in to the shift fork is in there. I think that there are 4 bolts holding it on. Also look at the surface on the gear where the fork rides and make sure that it looks ok.

Does anyone have or can anyone tell me where to get a illustration or diagram of the front axle so I know what I am looking for in the shift fork and the gear????

when removing the axle tube to get to the shift fork, does the axle just slide out when removing the tube??

Ttt

Does anyone have or can anyone tell me where to get a illustration or diagram of the front axle so I know what I am looking for in the shift fork and the gear????

Here's a link to a diagram at LMC truck for the front differential actuator. Hope this helps. http://www.lmctruck.com/icatalog/cd/t112.html

sounds like the tip of the axle is broken of, this will cause the axle to fall a little and not let the engagement sleeve slide onto axle, cause::: axle tip support bearing had failed.

would that axle tip support bearing be the same thing as a output shaft bearing as shown in a axle schematic. Please go this link and see if that is the bearing that you are talking about (#5)
http://www.trademotion.com/partlocator/index.cfm?action=getLocator&siteid=213815&chapter=DP1008&appSectionid=20&groupid=10016&subgroupid=20059&componentid=60570&make=6&model=K1500%20pickup&year=1988&graphicID=T008130&callout=13&catalogid=1

no. just in front of #16 you can get just the bearing from gm dealer. the bearing you are looking at supports the back of the axle.

Thanks for the info, but which number would the bearing that you are talking about be??
Does that involve a complete teardown of the front differential??

no remove extension housing and the gear and bearing will be right there. the bearing doas not have a call out#, go to the dealer and they should be able to find it for you. bearing is in front of #16 gear.