4WD engages backing turning right

[DryDog]

I think the 4WD is engaged on my 91 X, all by itself. Backing (right) into my driveway engages the front axel. When I pull forward and turn right or left it makes a terrible Grrrrr noise like my knobby tire is rubbing on the wheel well. I think the noise is coming from the front diff area. Over this past winter it has done this a few times. The cure was push the dash button, drive a few feet forward engaged, push the button (4WD light goes out) and reverse 40 feet or so. After a couple times of this it released. I put a new hub on the left last week and inner wheel bearings, no change. So I took the guts out of the old hub and have that on, still no change. I am sure this is ringing a bell for someone but I am stumped.

I put it on 4 jack stands, cranked the steering wheel full right...and the axel engaged. ???

 

[DryDog]

When I pulled off the right hub, the gear ring fell out in my hand. All that slop had it engaging. I should have bought 2 hubs. If anyone gets the new designed auto hub (1A Auto) 1AFWH00001, you will have to go to Ford for the new spacers F57Z-3B458-A.