While your wheelin', have someone look at your axle to see if you axle shaft is spinning. If the U-joint is spinning, then you have a hub problem, and if its not spinning, then the locker is not engaged.
TJ

 

If I jack up just that wheel, I shouldn't be able to turn it with the hub locked in, right?

'86 CJ-7, 360, TR ignition, 727, OEM Dana 44 rear w/Truetrac, Dana 30 w/Powertrax No-Slip, 4" Superlift, 4:11s, Warn HS9500i

 

Yea, you should be able to turn it. That is the feature of the locker. Without any acceleration from the drive shaft, you should be able to turn one wheel. What the locker does is to unlock to allow one wheel to spin faster than the other while turning. you could jack up the whole front end and turn the front drive shaft to see that both wheels turn (with the hubs locked).
Hope that helps alittle.
TJ