2020 International LT Fluid Type Specs

Quick Reference

Fluid	Type/Spec	Capacity
Engine Oil	SAE 10W-30 or 15W-40, API CK-4 / FA-4 (depending on engine)	Varies by engine (e.g., Cummins X15, Navistar A26)
Engine Coolant	Extended Life Coolant (ELC), OAT, Red/Purple,满足ASTM D6210 capacity varies.	40-70 Quarts (approx., varies by configuration)
Transmission	Varies by transmission (e.g., Eaton Endurant, Allison RDS)	Varies by transmission
Front Axle Diff	SAE 80W-90, API GL-5	Varies by axle model
Rear Axle Diff	SAE 80W-90, API GL-5	Varies by axle model
Brake Fluid	DOT 4 (Hydraulic Systems)	As needed (varies)
Power Steering	Dexron-III/Mercon or specialty fluid (verify in manual)	Varies
Washer Fluid	General Purpose Washer Fluid	1-3 Gallons (approx.)
DEF	API Certified Diesel Exhaust Fluid, ISO 22241	10-20 Gallons (approx.)

Engine Oil

For the 2020 International LT, the engine oil specification is crucial for the longevity and performance of its heavy-duty diesel engines. The primary engines offered in this model, such as the Cummins X15 and International A26, require oils meeting strict API (American Petroleum Institute) standards for diesel engines.

Type/Spec: You will generally find recommendations for SAE 10W-30 or SAE 15W-40. The critical specification to look for is API CK-4 or API FA-4. API CK-4 oils are successor to CJ-4 and are designed for a wide range of diesel engines, including those with Exhaust Gas Recirculation (EGR), Diesel Particulate Filters (DPF), and Selective Catalytic Reduction (SCR) systems. API FA-4 oils are a new category designed specifically for certain 2017 and newer diesel engines to provide improved fuel economy; however, FA-4 oils are not backward compatible with older engines or non-FA-4 specified engines. Always verify in your owner's manual or OEM service information which API spec (CK-4 or FA-4) is approved for your specific engine and model year. Using the incorrect spec can lead to premature wear and potential engine damage.

Capacity: Engine oil capacity varies significantly based on the specific engine model and configuration (e.g., oil pan size, presence of auxiliary filters). For example, a Cummins X15 might hold around 40-48 quarts, while an International A26 could be similar. Always consult your owner's manual for the exact capacity for your truck.

Intervals & Pitfalls: Follow the manufacturer's recommended oil change intervals, which can range from 25,000 to 75,000 miles or more, depending on the engine, duty cycle, and oil analysis results. Using oil analysis is highly recommended for optimizing drain intervals and detecting potential engine issues early. Never mix different types or brands of oil unless explicitly stated by the manufacturer, and always ensure the oil meets the required API specification.

Engine Coolant

Type/Spec: The 2020 International LT typically uses an Extended Life Coolant (ELC), which is an Organic Acid Technology (OAT) coolant. These coolants are usually red or purple in color. It is imperative to use an ELC that meets ASTM D6210, which is the performance standard for fully formulated, heavy-duty coolants. International often has its own internal specifications as well, but meeting ASTM D6210 is a strong indicator of suitable coolant. Avoid mixing different types of coolant (e.g., OAT with traditional IAT or HOAT coolants), as this can lead to gel formation, precipitate drop-out, and corrosion protection degradation, potentially causing severe damage to the cooling system.

Capacity: Coolant capacity ranges significantly depending on the engine, radiator size, and whether the truck has an auxiliary heater or other accessories. Expect capacities to be in the range of 40-70 quarts (10-17.5 gallons) or more. Refer to your owner's manual for the precise capacity.

Intervals & Pitfalls: ELCs have much longer service lives than conventional coolants, often lasting 600,000 miles or 6 years or even longer with proper maintenance and SCA (Supplemental Coolant Additive) testing/replenishment where applicable (though many OATs are "fill for life" and don't require SCA). However, it's crucial to monitor coolant quality and level. A yearly inspection is recommended. Ensure the system is bled properly after any coolant service to prevent air pockets.

Transmission Fluid

The International LT can be equipped with various heavy-duty transmissions, including Eaton manual and automated manual transmissions (AMTs) like the Endurant series, and Allison automatic transmissions (e.g., RDS series). As such, transmission fluid specifications will vary.

Type/Spec:

• Eaton Transmissions: Many Eaton manual and automated manual transmissions specify their own proprietary fluid, such as Eaton PS-164 Rev 7 or Eaton PS-386. Always check the specific Eaton model nameplate and your owner's manual for the exact fluid requirement. Using incorrect fluid can void warranties and cause catastrophic transmission failure.
• Allison Transmissions: Allison automatic transmissions typically require fluids meeting Allison TES-295 or Allison TES-389 specifications for their fully synthetic long-drain fluids. For specific models within the RDS (Rugged Duty Series) or other Allison lines, refer to the Allison Operator's Manual for your transmission which will precisely list the approved fluids.

Capacity: Transmission fluid capacities are highly dependent on the transmission model. Eaton AMTs might hold 13-16 quarts, while Allison automatics can range from 20-80 quarts or more depending on the model and external cooler configuration. Always refer to the specific transmission manual.

Intervals & Pitfalls: Follow the transmission manufacturer's recommended service intervals. For many heavy-duty transmissions using synthetic fluids, intervals can be 250,000 to 500,000 miles or several years. However, severe duty cycles, high temperatures, or specific applications may necessitate shorter intervals. Always ensure the transmission is filled to the correct level using the specified fluid. Never use "universal" ATF; always use the manufacturer-approved fluid to prevent damage.

Front and Rear Differential Fluid

Type/Spec: Axles in the 2020 International LT (which can be from various manufacturers such as Meritor, Dana, or International’s own offerings) generally require a SAE 80W-90 or SAE 85W-140 gear oil meeting API GL-5 specification. Some applications, especially those operating in extremely hot climates or under severe load, may specify a synthetic 75W-90 or 75W-140. For limited-slip differentials (less common in heavy trucks but possible for certain vocational applications), an additive package for limited-slip differentials will be required, or a fluid specifically formulated for LSDs. Always verify the exact specification on the axle tag or in the owner's manual.

Capacity: Differential fluid capacities vary based on the axle model and size. A typical drive axle might hold 15-25 quarts per differential. Tandem axle configurations will have two rear differentials (forward and rear-rear). Consult your axle manufacturer's specifications.

Intervals & Pitfalls: Differential fluid intervals are generally long for heavy-duty applications, often in the range of 100,000 to 250,000 miles under normal operating conditions. Regular inspection for leaks and fluid level is crucial.

Brake Fluid

For trucks with hydraulic brake systems (less common in Class 8 trucks which often use air brakes, but applicable to certain configurations), or for the clutch master/slave cylinders on some manual transmission trucks:

Type/Spec: The common specification for hydraulic brake systems is DOT 4. DOT 4 fluid has a higher wet and dry boiling point than DOT 3, making it suitable for heavy-duty applications. Always use new, sealed brake fluid, as it is hygroscopic (absorbs moisture) and its performance degrades over time once exposed to air.

Capacity: As needed for topping off or bleeding the system. A typical system flush might require 1-2 liters.

Intervals & Pitfalls: Brake fluid should typically be flushed and replaced every 2-3 years, regardless of mileage, due to its hygroscopic nature reducing its boiling point and increasing the risk of corrosion in the brake system.

Power Steering Fluid

Type/Spec: Power steering systems in the 2020 International LT can vary. Some systems may specify a standard Dexron-III/Mercon compatible automatic transmission fluid (ATF), while others may require a specific heavy-duty power steering fluid designed for commercial vehicles. It is critical to check the power steering reservoir cap or your vehicle's owner's manual for the exact required specification.

Capacity: Typically 3-6 quarts for the reservoir and system.

Intervals & Pitfalls: Power steering fluid generally has a long service life, but inspecting it for clarity and ensuring sufficient level is important during routine maintenance. If the fluid appears dark or smells burnt, it should be changed.

Washer Fluid

Type/Spec: Any general-purpose windshield washer fluid is acceptable. For cold climates, ensure it contains antifreeze properties to prevent freezing.

Capacity: Washer fluid reservoirs typically hold 1-3 gallons.

Intervals & Pitfalls: Top off as needed. No specific service interval.

Diesel Exhaust Fluid (DEF)

Type/Spec: Diesel Exhaust Fluid (DEF) is essential for the Selective Catalytic Reduction (SCR) system used in the 2020 International LT to meet emissions regulations. DEF must be API Certified and meet the ISO 22241 standard. It is a non-toxic solution of 32.5% high-purity urea and 67.5% deionized water. Never use any other fluid in the DEF tank, and ensure cleanliness when filling.

Capacity: DEF tank sizes vary but are typically in the range of 10-20 gallons for a Class 8 truck, providing enough range to coincide with typical fuel fill-ups.

Intervals & Pitfalls: DEF consumption is typically 2-3% of fuel consumption. Refill as needed. Store DEF properly as it has a shelf life (usually 1-2 years), which can be reduced by exposure to direct sunlight and high temperatures. Never contaminate DEF with fuel, oil, or water, as this will damage the SCR system and lead to costly repairs.

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