The PPE Silicone Bushing Engine Mount Kit - 50 SHD (OE Firmness) & 40/50/60/70 Harness that is designed to minimize noise, vibration, and harshness (NHV) in your 2001-2010 GM 6.6L Duramax. As the stock bushings wear down, the factory engine mounts will fail. Engine noise and vibration become more noticeable when they fail. This degradation is enhanced in high-power engine applications.