Also its not commonly known that the rear axle does in fact steer.

No, I'm not smoking crack either. On a solid rear axle the entire assembly rotates slightly as the body rolls. The direction of the rotation is to induce under-steer. This understeer is important in maintaining vehicle stability.

If you have a roll oversteer in the rear axle any disturbance will and create an instability and make the vehicle hard to keep straight. As you steer into a corner having the rear axle add to you input can get tricky.

You can see how roll understeer is implemented in a leaf spring vehicle. The front spring eyes are lower that the rear spring eyes. This spring angle causes the rear axle to steer the vehicle in the opposite direction of the driver input as the body rolls from cornering.

Kevin