Front axle won't engage

[6.2Blazer]

The most obvious thing mentioned in the diagnosis is that with the hubs locked you can spin the tire on one side and the axleshaft does not spin. This is an obvious problem and the first thing you should further investigate. Simply put the tire/wheel/hub is not engaging with the axleshaft. This typically means either the locking hub is installed incorrectly or the stub shaft is broken.

With a standard open diff this issue would make it appear the 4wd is not working at all since all of the power is being routed towards side that is not engaging, which effectively means zero resistance.

As a couple points of clarification, if you jack both front tires off the ground, lock in the hubs (which are actually working), and leave the t-case in 2wd. For an open diff, if you spin the tire on one side you can have the other side tire spin the opposite direction but the driveshaft (axle to t-case) will not move, OR the other side tire will not move but the driveshaft will spin. Just depends as the power will flow through the path of least resistance, and if you do the same thing several times you might get the other side wheel spinning one time and then the next the driveshaft will spin.

 

[rjfguitar]

The most obvious thing mentioned in the diagnosis is that with the hubs locked you can spin the tire on one side and the axleshaft does not spin. This is an obvious problem and the first thing you should further investigate. Simply put the tire/wheel/hub is not engaging with the axleshaft. This typically means either the locking hub is installed incorrectly or the stub shaft is broken.

With a standard open diff this issue would make it appear the 4wd is not working at all since all of the power is being routed towards side that is not engaging, which effectively means zero resistance.

As a couple points of clarification, if you jack both front tires off the ground, lock in the hubs (which are actually working), and leave the t-case in 2wd. For an open diff, if you spin the tire on one side you can have the other side tire spin the opposite direction but the driveshaft (axle to t-case) will not move, OR the other side tire will not move but the driveshaft will spin. Just depends as the power will flow through the path of least resistance, and if you do the same thing several times you might get the other side wheel spinning one time and then the next the driveshaft will spin.

This. Your lockout hub is installed incorrectly, is broken, or you have a broken stub shaft.

 

[K85 Octane]

OMG I said that post #4

Open up passenger side hub.

 

[Fordum]

Hang on. I agree with most everything here, well maybe I have some different thoughts about the skinny jeans.........

But, lets do something simple before tearing anything down or pulling covers.

Lift the front end again, one wheel at a time if necessary. Take a long screwdriver, and slide it into the "knuckle" U-joint at the end of the axle shaft just in board from the tire so the axle cannot turn.
Lock the hub on that side, and try to turn the tire.
If it can turn with the screwdriver stopping the axle from turning, that is a problem that you need to check out first.
Either the stub axle is broken inside the spindle housing, or the hub is not working.

Pull the hub, grab the end of the stub and try to turn it. If its locked by the screwdriver, then the hub is not working.
If it turns, the shaft is broken.

Once you get both axles definitely locked in with the hubs, then we can start looking for the next problem.