Before we started the install, we wanted to see just how inadequate the stock open differential was. We placed the right wheel and tire on a zero-traction roller device and strapped the axle to a pole with a scale that measures pulling force between them. The wheel with no traction spun and the one on the ground didn't do much at all. When we were done, the scale had recorded only about 20 pounds of pulling force. There's definite room for improvement.