Richmond directly and spoke with Jeff. He suggested to use the Richmond Gear Oil for break-in. For the break-in, Jeff stated "Drive 30-40 MPH for 30 Minutes, let cool for 30 minutes. Repeat this process 3 times. Drive car 200 Miles, then drain and replace with Richmond Gear Oil." Jeff went on to say that the most important thing during break-in is that the gears go through their "heat cycle." That's straight from the source, so that's the procedure I'm going with. GPA