Formulated to meet demanding extended service and original equipment manufacturer (OEM) warranty requirements, fully synthetic Mobil Delvac 1 Transmission Fluid 50 is recommended for year-round lubrication of manual transmissions in light- to severe-duty on- and off-highway equipment such as commercial line haul, vocational, off-road, pick-up and delivery and bus applications, and rear axles in conjunction with Mobil Devac 1 Gear Oil to enhance component life and fuel economy. Mobil Delvac 1 Transmission Fluid 50 meets or exceeds the requirements of the API service MT-1 EP gear oil service classification. It is suitable for use in transmissions and gear cases where API Service GL-1 through GL-4 gear protection is required. This product is also approved against the Mack TO-A Plus 500,000-mile extended service classification for Mack T300 series manual transmissions. With a viscosity index of 146, Mobil Delvac 1 Transmission Fluid 50 provides excellent shear stability, which ensures viscosity retention even under severe heavy-duty, high-temperature operating conditions.