2022 International LT Complete Fluid Specifications

As an ASE-certified master technician, I know firsthand that keeping a Class 8 heavy-duty truck on the road requires strict adherence to OEM maintenance schedules. The 2022 International LT is a cornerstone of the modern freight industry, commonly equipped with either the International A26 (12.4L) or the Cummins X15 (15.0L) engine, along with a variety of Eaton or Allison transmissions and Meritor or Dana axles.

Using the wrong fluid in any of these sophisticated, high-dollar components can lead to catastrophic failure, voided warranties, and massive downtime. Below is your comprehensive guide to the factory-spec fluids for the 2022 International LT.

Quick reference

Fluid	Type/Spec	Capacity
Engine Oil (Cummins X15)	API CK-4 / FA-4 (10W-30, 5W-40, 15W-40)	44 - 46 Quarts
Engine Oil (International A26)	API CK-4 / FA-4 (10W-30, 5W-40, 15W-40)	40 - 42 Quarts
Engine Coolant	OAT ELC (Navistar CEMS B-1 Type III / Cummins CES 14603)	12 - 15 Gallons (varies by sleeper/radiator)
Transmission Fluid (Eaton Automated)	PS-386 Synthetic Transmission Fluid (SAE 50W)	16 - 28 Pints (varies by model)
Transmission Fluid (Allison Auto)	Allison TES 668 or TES 295	30 - 40 Pints (varies by model/pan)
Drive Axles / Differentials	Synthetic 75W-90 or 80W-140 (Meritor O-76-N / Dana SHAES 256 Rev C)	30 - 40 Pints (per axle)
Brake Fluid	N/A (Air Brake System)	N/A
Power Steering Fluid	Dexron III / Heavy-Duty PS Fluid (Navistar Spec)	4 - 5 Quarts
Diesel Exhaust Fluid (DEF)	ISO 22241	15 - 23 Gallons (varies by tank option)
Windshield Washer Fluid	Standard all-season solvent	1 - 2 Gallons

(Note: Capacities are approximate and depend heavily on the specific truck configuration, oil pan size, transmission PTOs, and sleeper heater options. Always verify in the owner's manual or OEM service info before filling.)

Engine Oil

The 2022 International LT primarily relies on either the Cummins X15 or the International A26 engine. Both engines mandate the use of heavy-duty diesel engine oil meeting the API CK-4 or the newer, fuel-efficient API FA-4 specification.

Weight / Viscosity: The factory fill is typically 10W-30 for optimal fuel economy. However, 5W-40 or 15W-40 can be used depending on your operating climate. Pitfalls: Do not mix API CK-4 with older CJ-4 or CI-4 oils if you can avoid it, and absolutely never use passenger car motor oil. API FA-4 oils have lower high-temperature high-shear (HTHS) viscosity, so verify your specific engine serial number is approved for FA-4 before switching from CK-4. Stick strictly to the OEM oil drain intervals, which can range from 30,000 to 75,000 miles depending on idle time and fuel efficiency (MPG).

Engine Coolant

Modern diesel engines run incredibly hot and rely on wet-sleeve cylinder liners that are susceptible to cavitation if the wrong coolant is used. The 2022 International LT requires an Organic Acid Technology (OAT) Extended Life Coolant (ELC). Specs: Look for coolant meeting Navistar CEMS B-1 Type III (for the A26) or Cummins CES 14603 (for the X15). This is typically a red or yellow Nitrite-Free ELC. Pitfalls: Never mix OAT coolant with older HOAT (Hybrid) or conventional green silicated coolants. Doing so will precipitate the additives out of the solution, turning your coolant into an abrasive gel that will destroy your water pump and clog the EGR cooler.

Transmission Fluid

Transmission specs depend entirely on the unit optioned in your LT:

• Eaton Endurant / Fuller Manuals: Require a specialized synthetic transmission fluid meeting Eaton PS-386 (often a 50W synthetic). Never use conventional gear oil (like 80W-90) in these, or you will ruin the synchronizers and gears.
• Allison Automatics: Require fluid meeting the Allison TES 668 specification (which superseded TES 295). Never use universal ATF, Dexron VI, or Mercon LV in a heavy-duty Allison transmission.

Transfer Case

The International LT is a Class 8 highway tractor, predominantly configured as a 6x4 (two rear drive axles). It does not have a traditional transfer case like a standard 4WD pickup truck.

Drive Axles (Differentials)

The front (forward-rear) and rear (rear-rear) drive axles are typically supplied by Meritor or Dana. Specs: They require fully synthetic gear oil, usually SAE 75W-90 for standard duty and maximum fuel economy, or SAE 80W-140 for heavy haul/severe duty. The fluid must meet specific manufacturer specs such as Meritor O-76-N or Dana SHAES 256 Rev C. Pitfalls: Always clean the magnetic drain plugs during service. Do not use conventional gear oil, as thermal breakdown will occur rapidly under heavy freight loads, leading to catastrophic ring and pinion failure.

Brake Fluid

The 2022 International LT utilizes a heavy-duty pneumatic (air) brake system. Specs: There is no traditional liquid brake fluid (DOT 3/4/5.1) to check or fill. Instead, your maintenance focus here must be on the air dryer cartridge. You should replace the desiccant air dryer cartridge annually to prevent moisture buildup in the air lines, which can freeze in winter or cause valve corrosion.

Power Steering Fluid

The power steering system on the LT operates under immense pressure to turn massive steer tires. Specs: Navistar generally specifies a heavy-duty power steering fluid or an automatic transmission fluid like Dexron III. Pitfalls: Do not use universal power steering fluid meant for passenger cars. Ensure the system is properly bled if a hose or steering gear is replaced, as air pockets can cause pump cavitation and complete loss of steering assist.

Diesel Exhaust Fluid (DEF)

The Selective Catalytic Reduction (SCR) emissions system requires high-purity Diesel Exhaust Fluid. Specs: Must meet the ISO 22241 standard (32.5% high-purity urea and 67.5% deionized water). Pitfalls: Contamination is the number one killer of heavy-duty emissions systems. Never put DEF in the diesel tank, and never put diesel in the DEF tank. Even a drop of oil, dirt, or tap water in the DEF tank can permanently destroy the DEF doser and SCR catalyst, resulting in a multi-thousand-dollar repair and engine derate.

Windshield Washer Fluid

Use a standard commercial windshield washer fluid. In northern climates, ensure you are using a winter-blend washer fluid rated for at least -20°F to prevent the fluid reservoir and lines from freezing and cracking.

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