Removing the grease and adding 30,000 wt Silicone Diff oil really improves traction and handling (Keeps more power to the ground when one wheel comes up or loses traction - Like when cornering hard on higher bite surfaces). You won't be sorry! When you take the spider gears out of the diff, there is an ultra thin washer between each of the 4 beveled spider gears and the diff case - Don't lose them.