Okay heres something crazy i heard.. and tried.. but cannot explain how it works. My friend with a scsb 4x4 obs with a G80 never engaged. He said by depressing the emergency brake about 1/2 way down, enough to give it some resistance will "engage" the "locker." I had never heqrd of such a think so i tried it anyways. I climbed an off camber hill in my G80 equipped Suburban with 3.73. Hung one tire almost in the air and foward momentum stopped. Backed up, pressed the emergency brake half way down and hit the hill at the exact same angle. Got one tire spinning slowly then a little clank and it continued to climb all the way up the hill..
I got off the hill, released the emergency brake and drove it in a circle on pavement. One tire was chirping (as any tire would with a true locker/spool) after a few circles it made another clank and "disengaged" itself.
Any explanation for this?