Hi,
Yes, you are missing something. The handle to hold the "engagement block" out.
In your fourth photo down, the "engagement block" is the square block with the corners machined off.
The handle fits into the holes drilled in the side of the block.
To disengage the diff lock, the handle is pulled out, pulling the block against the spring, and sits over the
screw and washers.
To engage diff lock, you just lift the handle back over the side of the block, and the spring pressure engages the block.
You could make one up easy enough or go to your nearest Greenfield dealer and buy one.
