Shell Rotella Gas Truck 5W-30 has becoming popular lately because SUVs and pickup trucks are popular, and this oil claims to be tailored for them. However, is it for real or a marketing hype? I just did a quick calculation for it and Shell Rotella T6 Multivehicle 5W-30: Rotella Gas Truck 5W-30 KV40 = 66.4 cSt KV100 = 11.7 cSt VI = 173 density = 0.836 HTHS (estimated) = 3.0 cP Base-oil viscosity at 150 C (calculated/estimated) = 1.8 cP Relative VII content (calculated/estimated) = 10% Rotella T6 Multivehicle 5W-30 KV40 = 75 cSt KV100 = 12.1 cSt VI = 159 density = 0.845 HTHS (estimated) = 3.5 cP Base-oil viscosity at 150 C (calculated/estimated) = 2.6 cP Relative VII content (calculated/estimated) = 4% Rotella Gas Truck 5W-30 seems to be loaded with VII, which is exactly the opposite of what you want in a demanding engine like a gas-truck engine, as excess VII increases wear and increases engine and turbocharger deposits. However, higher VII content increases fuel economy. Rotella Multivehicle 5W-30 has a low VII content. The base oil is very thick, which will reduce wear. Engine and turbocharger deposits will also be less. However, the fuel economy will be lower. Moral of the story: Don't go with the marketing hype -- go with the certifications. Rotella Gas Truck 5W-30 has the same certifications as any synthetic 5W-30. Rotella T6 Multi-Vehicle 5W-30 packs all kinds of heavy-duty certifications and OEM approvals. If you are looking for a better oil, you can also look for ACEA certifications. Disclaimer: The calculations/estimates are only based on the viscosity data. There is no way to estimate the quality of the additive pack without engine and bench tests, other than from the certifications/OEM approvals claimed.