When this car was assembled, the guys at the plant set up the ring-and-pinion with the correct combination of shims to prevent gear noise. Because we are using Ford parts, theoretically, the original combination of shims should work. So Moore pressed the bearing off the pinion to reuse the stock pinion shim. “That shim goes with that case; it should work with these new gears, too. With factory gears you can usually reuse the stock shims. But you’re usually not as lucky with aftermarket gears. You will have to install them, check the pattern, and remove or add shims until the pattern is correct,” Moore says.