Truck Repair: pulling to one side, ford bronco ii, friction clutch

Question
I have a 1990 Ford Bronco II with an electronic 4x4 shift and auto locking hubs.  The other day I engaged the 4x4 (not on the fly) and my vehicle started pulling hard to the right in both high and low.  After disengaging and unlocking the hubs and in 2 hi my vehicle seemed ok (no pulling).  I tried to swap the hubs R to L and L to R.  When I engaged 4 HI it appeared ok, but when I went to low it again pulled hard right.  Now both in low and again in hi.  I disengaged the 4x and drove backwards to unlock the hubs.  It was now pulling hard left in reverse and was making a loud noise during movment.  I then went forward and my vehicle appeared to be ok again with no pulling in 2 hi nor any noise.  Just tonight I was trying to remove my front driveshaft for transmission removal.  The driveshaft was free for two turns then decided to lock in place. I am confused by this and if you can shed any light on this it would be helpful.

FYI I do know that my shift motor is engaging.  I try to engage the 4x4 once a month to keep this working.  I had not done this for the last 2 months when I now have this problem.

Answer
Hi Josh,
First lets do the driveshaft turning part.
Normally, when not in 4X4, the front driveshaft is not turning.
When you engage 4X4, the front shaft turns, and due to the friction clutch in the wheel hubs, the rotation of the axle shafts engages the hubs. The turning of the driveshaft is necessary and normal.

Now, as to why yours is pulling after engaging, the stub shaft on the front axles, that go from the axle "U"joints thru the spindle to the hub, are supported by a needle bearing inside the spindle. The seal for that area is not great, and those bearings get water and mud in them, and lock up.

I would remove the one on the side that is pulling and check it out.

You can also jack the front up, rotate the driveshaft to engage the hubs, then rotate the wheel by hand, and you will probably be able to tell that the right one won't like to rotate as long as the hub is locked.
Rotate it in the other direction till it unlocks, and then see that it rotates freely.

Van