09 If you aren't placing the differential and gears, shims would not be an issue. Since we are, we need to shim the pinion gear bearing accordingly. The pinion gear typically has the required pinion-depth measurement etched on its face. With a pinion depth gauge, setting this depth is easy. Without a pinion depth tool, it's impossible to know exactly what shims are needed. A good starting point is to use the same amount of shims as the original pinion did. Without a depth gauge, it's going to be a trial and error install to get the depth correct.