Triax Fleet Supreme 15W-40 Full Synthetic Diesel Oil - Extended Drain

Our review of the Triax Fleet Supreme 15W-40 finds it aimed squarely at owners of heavy duty diesel trucks who want quieter operation, better fuel economy and dramatically extended drain intervals. The single biggest reason to consider this oil is its friction-modified formula with Nano-Boron and Moly that delivers markedly lower wear and smoother turbo spooling, translating to longer engine life and less downtime for fleet and pickup owners.

Key Features

• Friction Modified: Nano-Boron and Moly friction modifiers reduce friction for smoother turbo spooling and improved component life.
• Extreme Wear Protection: Formulated to deliver up to 48% lower wear versus typical industry standards, protecting bearings and cylinders under load.
• Extended Drain Intervals: High shear stability and film strength support drain intervals beyond 100,000 miles on highway semis and 30,000 miles on Super Duty pickups.
• Cold Start Performance: Exceptional low-temperature flow and protection down to -45 F help maintain reliable starting and lubrication in extreme cold.
• DPF and SCR Safe: Designed to keep diesel particulate filters clean and prevent clogging while remaining compatible with CK-4 and prior diesel engines.

Who It's For

This oil is well suited for fleet managers, owner-operators and owners of heavy duty diesel pickup trucks from Powerstroke, Duramax, Cummins and similar platforms who tow, haul or cover long highway miles. The formula benefits anyone seeking quieter idling, improved mileage and peace of mind from extended drains.

Those with very short-trip urban drivers or vintage diesel engines with atypical additive requirements should evaluate local service intervals and compatibility before switching, since the product is optimized for modern CK-4 and heavy duty applications rather than niche antique engines.

Pros & Cons

Pros

• Noticeably quieter operation and smoother idle reported by owners, indicating effective friction reduction.
• Improved fuel economy in real use, with customers noting MPG gains and the product claiming 4-6% improvement.
• Long drain capability and strong shear stability reduce maintenance frequency for highway duty.
• Built-in additives eliminate the need for aftermarket friction or anti-stiction additives for HEUI injectors.

Cons

• Premium, fully synthetic formulation may cost more per gallon than conventional oils for low-mileage vehicles.
• Extended drain recommendations require disciplined oil analysis and adherence to fleet maintenance practices to realize full benefit.

Specifications

Our Verdict

Triax Fleet Supreme 15W-40 is a strong choice for heavy duty diesel owners who prioritize engine longevity, quieter operation and extended drain intervals. Its friction-modified, full synthetic formula delivers real-world improvements in wear protection and fuel economy, making it a worthwhile investment for fleets and towing pickup owners seeking lower operating costs over time.

Frequently Asked Questions

Is this oil compatible with my diesel truck?
Yes, it is fully compatible with CK-4 and earlier heavy duty diesel engines including Powerstroke, Duramax and Cummins platforms.

Do I need to add extra additives?
No, the formula includes Nano-Boron and Moly and is designed to eliminate the need for aftermarket anti-stiction or friction additives.

Can I really extend drain intervals that far?
Yes, the oil is engineered for long drains, but fleets should confirm with oil analysis and manufacturer service plans before extending intervals.