Shell Oil - Rotella T4 Triple Protection Heavy-Duty Diesel Motor Oil - 5 Gallons - 550045128. Shell Rotella T4 Triple Protection 15W-40 is designed to provide hardworking protection that adapts to your driving conditions. With millions of miles of real world testing, Shell Rotella T4 Triple Protection 15W-40 uses a proprietary, synthetic blend formula exclusive to Shell. It is designed to protect under the most severe engine conditions found in modern low-emission engines and older hard working