2022 International LT Transmission Fluid & Service Guide

The 2022 International LT is a staple of modern linehaul fleets, renowned for its efficiency, driver comfort, and advanced powertrain integration. Depending on how your truck was spec’d, it is most commonly equipped with the highly efficient Eaton Cummins Endurant 12-speed Automated Manual Transmission (AMT), though Allison automatic transmissions (such as the 4000 Series) are also available for specific vocational or heavy-hauling applications.

Proper maintenance of the transmission is critical to minimizing downtime and maximizing the return on investment for your fleet. Below is your comprehensive guide to the transmission fluid, capacities, and service procedures for the 2022 International LT.

Quick answer: 2022 International LT Transmission Specs

Please note: The specifications below apply to the standard Eaton Cummins Endurant 12-speed AMT. If your LT is equipped with an Allison automatic or a different Eaton Fuller manual, capacities and fluid types will differ.

• Transmission Make/Model: Eaton Cummins Endurant 12-Speed AMT (Automated Manual Transmission)
• OEM Fluid Spec: Eaton PS-386 Synthetic Transmission Fluid
• Drain & Fill Capacity: Approximately 16 pints (8 quarts / 7.5 liters)
• Full Overhaul Capacity: Approximately 16 pints (8 quarts / 7.5 liters)
• Filter OEM Part Number: Verify with dealer or service manual (AMT lube filter part numbers can vary by exact transmission sub-model and build date)
• Recommended Service Interval: Up to 750,000 miles for standard linehaul; 500,000 miles for severe duty/heavy haul.

Fluid type explained

For the Eaton Cummins Endurant AMT, the lifeblood of the gearbox is Eaton PS-386 synthetic transmission fluid (often branded as Roadranger). This fluid was specifically engineered to improve fuel efficiency, reduce operating temperatures, and extend component life in Eaton's heavy-duty transmissions compared to older PS-164 rev 7 specifications. It offers superior shear stability and oxidation resistance, which is exactly why the Endurant can achieve such incredibly long service intervals.

If your 2022 International LT is equipped with an Allison 4000 Series automatic, the required fluid is TES 668 (which supersedes the older TES 295 spec). Always check the transmission data tag on the side of the gearbox before purchasing fluid, as mixing AMT fluid with Allison automatic fluid will cause catastrophic failure.

Service procedure

Because the Eaton Cummins Endurant is an automated manual transmission, the fluid service procedure is more akin to a traditional manual gearbox than a torque-converter automatic. There is no torque converter to trap fluid, meaning the drain and fill capacity is virtually identical to the dry/overhaul capacity.

1. Preparation: Drive the truck to bring the transmission fluid up to operating temperature. This ensures the fluid flows freely and suspends any wear particles.
2. Draining: Park on a level surface. Remove the drain plug at the bottom of the transmission case. Allow the fluid to drain completely. Inspect the magnetic drain plug for excessive metal shavings—a fine paste is normal, but larger chunks indicate internal gear or bearing wear.
3. Filter replacement: If your specific Endurant model utilizes a replaceable spin-on or cartridge lube filter, remove and replace it now. Coat the new filter seal with a thin layer of fresh PS-386 fluid before installing.
4. Filling: Remove the fill plug on the side of the case. Pump fresh Eaton PS-386 fluid into the fill hole until it is level with the bottom of the fill plug threads. Do not overfill.
5. Verification: Reinstall the fill plug, clean the area, and take the truck for a short test drive. Re-check the fluid level on a flat surface to ensure it is topped off correctly.

Service interval

The beauty of the Eaton Cummins Endurant transmission lies in its exceptionally low maintenance requirements, driven by its precision engineering and synthetic fluid.

• Normal Duty (Linehaul): For standard over-the-road applications where the truck spends the majority of its time at highway speeds, Eaton recommends a fluid and filter change at a staggering 750,000 miles or 5 years, whichever comes first.
• Severe Duty (Heavy Haul / Regional): If the truck is frequently hauling maximum gross combination weights, operating in mountainous terrain, or subject to high-stop-and-go regional routes, the interval is reduced to 500,000 miles or 3 years.

For Allison-equipped trucks: Expect to change the TES 668 fluid and filters every 300,000 miles or 3 years under normal linehaul duty, but consult the Allison prognostic system on your dash, as it monitors fluid life in real-time.

Common transmission problems

The 2022 International LT with the Endurant AMT is generally highly reliable, but technicians do see a few recurring issues:

• Pneumatic and Electrical Faults: The Endurant relies heavily on mechatronics and air pressure to execute shifts. Air leaks in the transmission's pneumatic supply lines or a failing Transmission Control Module (TCM) harness can result in skipped gears, harsh shifting, or a "Transmission Fault" warning on the dash.
• Clutch Actuator Wear: While the gearbox itself is incredibly robust, the automated clutch actuator mechanism can wear out over hundreds of thousands of miles, leading to shuddering on takeoff or failure to engage the clutch properly.
• Fluid Leaks: Inspect the output shaft seal and the mating surfaces of the transmission housing during preventative maintenance. While rare on newer models, early detection of a weeping seal can prevent the transmission from running dry.

Keeping up with your fluid services and addressing minor air leaks promptly will keep your International LT shifting smoothly for years.

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