Triax Fleet Supreme 5 Gallon 15W-40 CK-4 Full Synthetic - Extended

In this review of the Triax Fleet Supreme 15W-40 CK-4 full synthetic diesel oil, the bottom line is simple: fleet operators and heavy-duty pickup owners who need long drain intervals and strong wear protection will benefit most. The reviewer found it particularly effective at reducing noise and improving turbo response while providing protection for severe service work. For anyone who runs highway miles, tows regularly, or wants improved cold starts and injector reliability, this oil delivers convincing real-world gains.

Key Features

• Moly and Nano-Boron friction modifiers: Significantly reduce wear and friction for longer component life under heavy loads.
• Extended drain capability: Formulated to support drain intervals exceeding 100,000 miles in highway use and large intervals for pickups, reducing downtime and service costs.
• Exceptional cold start performance: Maintains pumpability and protection down to -45 F, helping reliability in very cold climates.
• DPF and SCR protection: Keeps aftertreatment systems cleaner and helps prevent particulate filter clogging when used as specified.
• Quieter operation and MPG gains: Lowers operating temperature and cuts noise while delivering reported fuel economy improvements of about 4-6% in many applications.

Who It's For

The Triax Fleet Supreme 5 gallon jug is aimed at commercial fleets, owner-operators and owners of heavy-duty diesel pickups such as Powerstroke, Duramax and Cummins who need extended drain intervals and robust wear protection during towing, hauling, and long highway runs. The friction-modified formula is a good match for high-mileage trucks that see both highway and severe service.

Those who should look elsewhere include drivers who strictly follow OEM-specified short, frequent oil changes for warranty reasons or users who prefer conventional rather than full synthetic CK-4 formulations. Also, if your vehicle requires a different viscosity or a non-CK-4 spec, choose the oil grade your engine manufacturer specifies.

Pros & Cons

Pros

• Excellent wear protection thanks to moly and nano-boron additives that lower friction noticeably.
• Long drain capability reduces maintenance frequency and total cost of ownership for highway-driven rigs.
• Improves noise, smoothness and turbo spool, with reported MPG improvements from real users.
• Built-in protection against HEUI injector stiction, avoiding the need for aftermarket additives.

Cons

• Extended drain intervals may not align with some OEM warranty schedules, so check manufacturer recommendations before extending drains.
• As a high-performance full synthetic, initial cost per jug is higher than basic conventional oils, though total lifecycle cost can be lower.

Specifications

Product	Triax Fleet Supreme 15W-40 CK-4 Full Synthetic
Capacity	5 gallon
API Service	CK-4 (backward compatible)
Friction Modifiers	Nano-Boron and Moly
Cold Start	Rated to -45 F
Suggested Drain Interval	Highway: up to 100,000+ miles; pickups: up to 30,000 miles
Application	Heavy duty diesel trucks, fleet, pickups

Our Verdict

The Triax Fleet Supreme 5 gallon 15W-40 CK-4 full synthetic is a solid choice for fleets and heavy-duty pickup owners who want extended drains, superior wear protection and improved drivability. It represents good value where long service intervals and component life matter most, provided users confirm compatibility with their OEM maintenance policies.

Frequently Asked Questions

Is this oil compatible with my diesel pickup?
This CK-4 formulation is fully compatible with most heavy-duty diesel pickups including Powerstroke, Duramax and Cummins when 15W-40 is the required viscosity.

Can I extend drain intervals with this oil?
Yes, the formula is designed for very long drains (manufacturer notes highway drains exceeding 100,000 miles), but always verify against your engine maker's maintenance requirements.

Do I need extra additives for injectors or DPF protection?
No, the product includes additives that eliminate HEUI injector stiction and help protect DPF and SCR systems, so no aftermarket additives are necessary.