2023 International MV: Complete Fluid Type Specifications

As an ASE-certified master technician who spends a lot of time around medium-duty commercial trucks, I know firsthand that maintaining a 2023 International MV requires strict adherence to factory fluid specifications. Whether your MV is spec'd with the legendary Cummins B6.7 or the heavier-duty Cummins L9, keeping this workhorse on the road means using the exact fluids designed to handle high payloads, constant idling, and grueling duty cycles.

Using the wrong fluid in an Allison transmission or pouring standard automotive antifreeze into a heavy-duty diesel cooling system can lead to catastrophic downtime. Below is a comprehensive guide to the factory-spec fluids for the 2023 International MV series.

Quick Reference

Note: Capacities vary significantly based on chassis configuration, engine choice (B6.7 vs. L9), axle ratings, and transmission PTO setups. Always verify exact capacities in your owner's manual or OEM service info based on your specific VIN.

Fluid	Type/Spec	Capacity
Engine Oil (B6.7 & L9)	API CK-4 / Cummins CES 20086 (15W-40 or 5W-40 Synthetic)	15–18 qts (B6.7) / ~24 qts (L9)
Engine Coolant	Nitrite-Free OAT (e.g., Fleetguard ES Compleat OAT) / CES 14603	25–35+ qts (varies by radiator)
Transmission (Allison)	Allison TES 668 (Supersedes TES 295)	15–20+ qts (varies by pan depth)
Transmission (Eaton)	Eaton PS-386 Synthetic Transmission Fluid	Varies by model (14–24+ pints)
Differential (Rear/Meritor/Dana)	SAE 75W-90 or 80W-140 Synthetic (Meritor O-76 / Dana SHAES-256)	15–30+ pints (varies by axle)
Brake Fluid (Hydraulic)	DOT 4 Heavy Duty Brake Fluid	Verify in owner's manual
Power Steering Fluid	Dexron III / Allison TES 389	2–4 quarts
Diesel Exhaust Fluid (DEF)	API Certified / ISO 22241	5–15+ gallons (tank size varies)
Windshield Washer Fluid	Standard all-season solvent	~1 gallon

Engine Oil

The 2023 International MV is predominantly powered by Cummins diesel engines. For both the B6.7 and L9, the required engine oil specification is Cummins CES 20086, which aligns with the heavy-duty API CK-4 standard.

For most climates, a conventional or synthetic-blend 15W-40 is the standard factory recommendation. However, if your fleet operates in freezing winter temperatures, moving to a full-synthetic 5W-40 API CK-4 is highly recommended to prevent dry starts and ensure rapid turbocharger lubrication.

Common Pitfall: Never use older API CJ-4 or passenger car motor oils in these modern diesels. CK-4 is formulated specifically to handle the high soot loading and extreme shear forces of modern emissions-controlled engines while protecting the diesel particulate filter (DPF).

Engine Coolant

Modern Cummins engines use advanced Nitrite-Free Organic Acid Technology (OAT) coolant. The factory specification is Cummins CES 14603 (commonly filled with Fleetguard ES Compleat OAT, which is typically red/magenta).

Common Pitfall: Never mix older Conventional or Hybrid OAT (HOAT) coolants with Nitrite-Free OAT. Mixing coolant types can cause the corrosion inhibitors to drop out of suspension, leading to abrasive silicate dropout, ruined water pump seals, and clogged EGR coolers. Also, do not use SCA (Supplemental Coolant Additive) chemical filters with OAT coolants; use a standard blank coolant filter.

Transmission Fluid

The vast majority of International MVs are equipped with Allison Automatic Transmissions (such as the 2000, 2500, or 3000 series). Allison strictly requires a TES 668 approved fluid (which recently superseded the older TES 295 standard). Top-tier fluids like Castrol TranSynd 668 are the gold standard here.

If your MV is equipped with an Eaton Fuller manual or Automated Manual Transmission (AMT), you must use an Eaton PS-386 approved synthetic transmission fluid.

Common Pitfall: Never use universal "Multi-Vehicle ATF" or standard Dexron VI in an Allison commercial transmission unless you want to drastically shorten its lifespan and void your warranty. Only use fluids explicitly stamped with the Allison TES 668 approval number.

Differentials and Transfer Case

Medium-duty axles from Dana Spicer or Meritor demand heavy-duty synthetic gear lubricants. The standard factory specification is a fully synthetic SAE 75W-90 or SAE 80W-140 that meets Dana SHAES-256 or Meritor O-76 specs.

Extended drain intervals are achievable with these approved synthetics (often up to 500,000 miles in line-haul applications, though vocational/city trucks require more frequent changes). If your MV is equipped with a front driving axle (4x4), the front differential utilizes the same synthetic gear oil. Always check the axle tag for specific capacities and fluid requirements.

Brake System

The 2023 International MV can be spec'd with either air brakes or hydraulic brakes.

• Air Brakes: There is no brake fluid. The air compressor is lubricated by the engine's pressurized oil system.
• Hydraulic Brakes: Use a high-quality DOT 4 Heavy Duty Brake Fluid.

Common Pitfall (Hydraulic): DOT 4 fluid is hygroscopic and absorbs moisture from the air. In heavy-duty applications, water-contaminated brake fluid will quickly boil under heavy braking, leading to sudden pedal fade. Flush hydraulic brake systems every two years regardless of mileage. Never use silicone-based DOT 5 fluid, as it is incompatible with the ABS system.

Power Steering

The power steering system in the International MV typically calls for Dexron III or a fluid meeting Allison TES 389. A high-quality heavy-duty ATF provides the necessary hydraulic pressure and shear stability for the massive steering gears required to turn heavy front axles. Ensure the reservoir is kept clean, as dirt ingress is the number one cause of power steering pump failure in commercial applications.

Diesel Exhaust Fluid (DEF)

To keep the SCR (Selective Catalytic Reduction) system functioning correctly and prevent crippling derate codes, only use DEF that is certified to ISO 22241 standards.

Common Pitfall: DEF has a shelf life. It degrades quickly in high heat or direct sunlight. Do not hoard DEF in hot shops for years, and always ensure the dispensing funnels are perfectly clean. Even a microscopic amount of dirt, oil, or coolant introduced into the DEF tank can permanently destroy the DEF doser and NOx sensors.

Windshield Washer Fluid

Use any standard all-season windshield washer fluid. In freezing climates, ensure your fluid is rated for at least -20°F to prevent the reservoir and lines from cracking. Do not use plain water, as it breeds bacteria that can clog the washer pump screen.

Maintaining an International MV isn't hard, but it requires precision. Fluids are the lifeblood of this truck—don't cut corners.

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