Just read through this, and the discoweb link is for installing a CDl shifter on a D2. It uses a push button to activete the solenoid, which locks the diff... Has nothing to do with your situation.

If spraying the rods won't work, take it apart and clean it. After taking the linkage loose, try to move the nut on the top of the T-case. It is what locks the diff. If it is stuck, might have to tear down the T-case....