The vertical bulge in the front and rear axle cases allows the crown wheel to rotate inside. The crown wheel is a large gear that transfers the input drive into the differential and along the axle shafts. The bulge is pressed steel and when rammed into immovable objects such as rocks can easily be holed loosing valuable lubricating oil.
Terrafirma differential guards are easy to fit and offer protection against even the most aggressive attacks on obstacles.
