4WD Not Engaging - What did I do wrong?

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Feb 22, 2014
Spokane, WA
Back in October I rebuilt the front axle (new trunion bearings, wheel bearings, axle seals, birfields etc.) and everything went together as it should. I've put around 1000 miles on the truck since then without incident.

Fast-forward to yesterday and my 4WD doesn't work. I couldn't even get out of my own driveway. 4HI, 4Lo, doesn't matter. Not getting power to the front wheels.

So I brought it into my shop and lifted the front end. In 1st gear with the T-case in 2Hi, I'm able to spin the front driveshaft freely with limited to no resistance. In 1st gear with the T-case in 4Hi with the rear wheels still on the ground, I cannot rotate the front driveshaft whatsoever. This tells me that the T-case is engaged with the output from the transmission and should be translating power from the transmission/rear driveline through the T-case to the front driveline. Correct me if I'm wrong!

Moving onto the hubs, I took both out while in the "Free" position. The spline that engages the axle was recoiled in toward the hub. Moving the dial on the locking hubs to "Lock" allowed the spring to push outward and push the outer ring gear that would engage the front wheels to their correct position.

With both hubs in the "Lock" position and installed on the front axle, I am able to independently turn each front tire without the other spinning, and without rotating the front driveshaft. Rotating the front driveshaft in 2Hi with both hubs in the "Lock" position did not result in either wheel rotating.

Did I do something minor in my rebuild of the front axle to negatively affect the differential somehow? Or am I looking at a hub issue? I'm majorly confused because as far as I can tell from my -albeit somewhat limited- experience, this narrows it down to the differential, no? And if it was, wouldn't I be hearing some pretty unfriendly noises?

I'm stumped.

I appreciate any all responses.

It’s virtually impossible to damage the diff when rebuilding the axles. You put oil in it right? Just kidding.
So I’m guessing it’s your locking hubs. To me it looks like the part they call the lock ring could be put in backwards, maybe that’s the case. See how the inner teeth are towards the inside?
The hubs were installed incorrectly. They are not locking. Remove them and pay careful attention to the drawings in the FSM when reassembling them.

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