2022 International LT Transmission & Axle Gear Ratios

Transmission gear ratios

The 2022 International LT Series offers a variety of transmission options to suit different applications, primarily focusing on heavy-duty hauling and efficiency. The most common transmissions found in these trucks are Eaton Fuller manuals and Eaton automated manuals (AMT).

Eaton Fuller Advantage 10-Speed AMT (FO-16E310C-VXP)

Eaton Fuller Advantage 12-Speed AMT (FO-17E312C-VXP)

Available axle ratios

The choice of axle ratio significantly impacts the truck's performance characteristics, balancing between fuel efficiency and pulling power. International LT trucks are available with a range of Meritor and Dana Spicer axle ratios.

Note: Specific RPO/Axle codes can vary based on the exact axle manufacturer (Meritor, Dana) and International's internal coding system. Always refer to your truck's specific documentation.

How to identify your axle ratio

Identifying your International LT's axle ratio is crucial for proper maintenance, part replacement, and understanding its performance characteristics. International trucks, like many heavy-duty vehicles, typically have an RPO (Regular Production Option) sticker or tag that lists these details.

For International trucks, the RPO sticker is usually located on the driver's side door jamb or inside the glove compartment. Look for a label that lists various codes. The axle ratio code will often be a three-digit or four-digit alphanumeric code. Sometimes, the ratio is explicitly spelled out.

Alternatively, many heavy-duty axles have a metal tag attached to one of the differential cover bolts or cast into the axle housing itself. This tag will often contain information such as the axle model, serial number, and the gear ratio. If you cannot locate the sticker, a dealer or service center can often decode your VIN (Vehicle Identification Number) to provide the exact specifications, including the axle ratio.

Towing vs MPG impact

The axle ratio has a direct and significant impact on a truck's towing capability and fuel economy. Generally:

• Numerically Lower Ratio (e.g., 2.47, 2.64): This means the driveshaft makes fewer revolutions for each revolution of the wheel. This reduces engine RPMs at cruising speeds, leading to better fuel economy, especially during highway driving. However, it also reduces the mechanical advantage, making the truck feel less powerful when accelerating from a stop or when pulling heavy loads. This setup is ideal for long-haul applications where the truck spends most of its time at consistent highway speeds with lighter loads.

• Numerically Higher Ratio (e.g., 3.08, 3.21): With a higher ratio, the driveshaft makes more revolutions for each wheel revolution. This increases torque at the wheels, providing greater pulling power and better acceleration, which is essential for heavy towing, challenging terrain, or frequent stop-and-go driving. The trade-off is higher engine RPMs at cruising speed, which negatively impacts fuel economy.

Choosing the right axle ratio involves balancing these two critical factors based on the truck's primary application.

Common issues

While International LT trucks are built for durability, certain issues can arise with the drivetrain components, especially with high mileage or improper maintenance.

• Ring & Pinion Whine: A common symptom of worn or improperly set up differential gears. This often manifests as a howling or whining noise that changes with vehicle speed, acceleration, or deceleration. It can be caused by improper backlash, worn bearings, or damaged gear teeth.

• Carrier Bearing Wear: The carrier bearings support the differential carrier within the axle housing. Wear can lead to excessive play, vibration, and noise, eventually causing differential failure if not addressed. Symptoms often include a rumbling or growling noise, especially noticeable during turns or acceleration.

• Limited-Slip Differential (LSD) Clutch Wear: If equipped with an LSD, the clutches can wear out over time, leading to a loss of limited-slip function. This can manifest as a lack of traction in slippery conditions where one wheel spins freely, or a chattering noise during tight turns as the clutches struggle to engage smoothly.

Regular maintenance, including checking fluid levels and performing scheduled fluid changes, is critical to prolonging the life of these components.

Find a driveline shop on Repairius.