International T14 Transmission

Quick Facts

  • Manufacturer: International Motors
  • Transmission Type: Automated Manual Transmission
  • Transmission Name: International T14
  • Forward Speeds: 14, including two crawler gears
  • Reverse Speeds: 6
  • Top Gear: 0.78:1 Overdrive
  • Direct-Drive Gear: 13th Gear at 1.00:1
  • First-Gear Ratio: 20.81:1
  • Lowest Reverse Ratio: 16.23:1
  • Maximum Engine Torque: Up to 1,850 lb-ft with the International S13
  • Maximum Engine Power: Up to 515 horsepower with the International S13
  • Internal Design: Single-Countershaft Geartrain with Planetary Reverse
  • Clutch Type: Electronically Controlled Dry Clutch
  • Control Type: Fully Automated Two-Pedal Operation
  • Common Engine Pairing: International S13
  • Common Truck Applications: International LT, RH, HX, and HV Series
  • PTO Compatibility: Factory-Installed Single or Dual Transmission PTO; REPTO, FEPTO, Auxiliary Transmission, and Split-Shaft Support depending on configuration
  • Primary Applications: Long Haul, Regional Haul, Vocational Work, Construction, Dump, Paving, Heavy Haul, and Off-Road Operations
  • Production Status: Active Production

Overview

The International T14 is a 14-speed automated manual transmission developed specifically for the International S13 Integrated Powertrain.

Unlike an independently selected transmission paired with several unrelated engines, the T14 was designed alongside the S13 engine and International’s Dual Stage Aftertreatment system. The engine, transmission, and emissions system communicate as one integrated powertrain.

The T14 uses 14 forward ratios, including two deep crawler gears, and six reverse ratios. Its wide gear-ratio spread supports both fuel-efficient highway cruising and low-speed vocational operation.

A single-countershaft design reduces internal complexity, while planetary gearing provides reverse operation without requiring a separate conventional reverse gear section. This contributes to the transmission’s compact dimensions, lower weight, and available chassis space for PTO equipment.

The transmission entered the North American market first in highway-focused International trucks and has since expanded into the HX and HV vocational families. It now supports long-haul, regional, construction, dump, paving, off-road, and specialized vocational applications.

Key Characteristics

The T14 is built around a wide-ratio 14-speed design. First gear provides a 20.81:1 ratio, while 13th is direct drive at 1.00:1 and 14th is a 0.78:1 overdrive.

The first two forward ratios function as crawler gears. These deep reductions improve startability under heavy loads and provide precise vehicle movement during vocational work.

Six reverse ratios allow the operator and transmission controls to select an appropriate backing speed. This is particularly useful for trailers, dump operations, paving, construction sites, and vocational bodies requiring precise positioning.

The transmission uses a single countershaft rather than a traditional twin-countershaft arrangement. International describes this design as lightweight, efficiently packaged, and mechanically simplified.

Reverse is created through planetary gearing. Eliminating a separate conventional reverse-gear section reduces transmission size and leaves additional chassis space for PTO and body-equipment installation.

The electronically controlled clutch actuator works with the engine controls to deliver fast, smooth shifts and reduce speed loss between gears.

How the Transmission Works

The T14 is mechanically an automated manual transmission. It uses conventional geared power transfer but electronically controls the clutch and gear-selection process.

When the driver selects Drive, the transmission control module evaluates vehicle weight, grade, accelerator input, engine torque, vehicle speed, operating mode, and programmed application settings.

The transmission then selects an appropriate starting gear. A lightly loaded highway tractor may not need to start in the lowest crawler ratio, while a loaded vocational truck on a grade may use a deeper gear.

During a shift, the transmission and S13 engine coordinate torque output. Engine torque is briefly adjusted, the clutch and gear-selection system complete the change, and power is restored.

The T14 can skip unnecessary ratios when conditions allow. Under heavy loads or on steep grades, it can use more of the available gears to maintain engine speed and driveline control.

Thirteenth gear is direct drive. The transmission is designed to spend much of its normal highway operating time in this efficient 1.00:1 ratio. Fourteenth gear provides overdrive when vehicle speed, load, terrain, and axle gearing make it appropriate.

Reverse operation uses the transmission’s planetary gear set. This design provides six reverse ratios without requiring a large standalone reverse section.

The driver can select automatic or manual control modes, but the electronic system retains protective authority. It can reject an unsafe shift that would overspeed the engine, lug the powertrain, or conflict with operating parameters.

Common Specifications

Transmission Type

The International T14 is a two-pedal automated manual transmission with an electronically controlled dry clutch.

It does not normally use the torque converter and planetary forward gearing found in a conventional automatic transmission.

Forward Speeds

The transmission provides 14 forward speeds.

The first two ratios are deep crawler gears. Gears 3 through 13 provide the primary operating range, while 14th is overdrive.

Forward Gear Ratios

  • 1st: 20.81:1
  • 2nd: 16.16:1
  • 3rd: 12.57:1
  • 4th: 9.76:1
  • 5th: 7.56:1
  • 6th: 5.87:1
  • 7th: 4.55:1
  • 8th: 3.53:1
  • 9th: 2.77:1
  • 10th: 2.15:1
  • 11th: 1.66:1
  • 12th: 1.29:1
  • 13th: 1.00:1
  • 14th: 0.78:1

The approximately 29-percent steps between the forward ratios provide consistent progression through the gear range.

Crawler Gears

First and second gears serve as crawler ratios.

These gears provide strong startability and precise low-speed movement for construction, dump, paving, heavy-haul, and off-road applications.

Reverse Speeds

The T14 provides six reverse ratios using planetary gearing.

Reverse Gear Ratios

  • Reverse 1: 16.23:1
  • Reverse 2: 12.60:1
  • Reverse 3: 9.81:1
  • Reverse 4: 7.61:1
  • Reverse 5: 5.91:1
  • Reverse 6: 4.59:1

Higher reverse ratios should only be used under suitable operating conditions and according to International’s instructions.

Direct Drive

Thirteenth gear provides a direct 1.00:1 ratio.

The integrated powertrain is designed to operate efficiently in direct drive during many highway conditions, reducing unnecessary internal gear losses.

Overdrive

Fourteenth gear provides a 0.78:1 overdrive ratio.

Overdrive can reduce engine speed during suitable highway operation, but the control system may choose direct drive when that produces better efficiency or performance.

Torque Capacity

The T14 is paired with International S13 engine ratings reaching 1,850 lb-ft at approximately 900 rpm.

The complete engine, transmission, axle, and vehicle specification must be approved for the intended torque and duty cycle.

Horsepower Compatibility

Current S13 Integrated Powertrain ratings reach 515 horsepower.

Available ratings vary by truck model and application.

Internal Design

The transmission uses a single-countershaft geartrain designed to reduce mechanical complexity and operating weight.

Planetary gearing provides reverse operation and helps shorten the overall transmission package.

Clutch System

An electronically controlled clutch actuator manages clutch engagement during starting, stopping, and shifting.

The clutch remains a mechanical wear component even though the driver does not operate it with a pedal.

Electronic Controls

The transmission control module coordinates:

  • Starting-gear selection
  • Clutch engagement
  • Automatic shifting
  • Manual shift requests
  • Eco-Coast
  • Downhill Speed Control
  • Hill Hold
  • Drive modes
  • Auto Neutral
  • Low-speed maneuvering
  • PTO functions
  • Vocational programming

Operating Voltage

The T14 uses dedicated electrical architecture as part of the S13 Integrated Powertrain. Service procedures must follow International’s requirements for its transmission controls and electrical system.

Lubrication

The transmission uses approved 75W-80 lubricant.

Published service information lists approximate capacities of:

T14 without a transmission-mounted PTO: Approximately 21.3 pints

T14 with a single or dual transmission PTO: Approximately 24.1 pints

The exact lubricant specification and capacity must be confirmed using the truck’s VIN and current International service information.

Cooling System

An oil-to-water cooling system helps regulate transmission temperature during highway, vocational, and high-load operation.

Cooling-system condition is particularly important in low-speed vocational service where airflow may be limited.

PTO Compatibility

Available PTO arrangements include:

  • Single transmission-mounted PTO
  • Dual transmission-mounted PTO
  • Rear-engine PTO
  • Front-engine PTO
  • Split-shaft PTO support
  • Auxiliary-transmission programming

International offers factory-installed single and dual transmission PTOs with common SAE interfaces on compatible configurations.

Vocational Drive Modes

Available vocational programming can include:

  • Paver Mode
  • Off-Road Mode
  • Split-Shaft Mode
  • Maneuvering Mode
  • Downhill Speed Control
  • Hill Hold
  • Auto Neutral

Application availability depends on truck programming and the completed vehicle specification.

Transmission Weight

International emphasizes the T14’s reduced size and weight compared with many traditional heavy-duty transmissions. Exact installed weight can vary with the clutch, PTO provisions, cooler, software, and vocational equipment and should be confirmed for the ordered configuration.

Installation Requirements

The T14 requires the International S13 Integrated Powertrain’s compatible engine controls, transmission controller, electrical architecture, clutch system, cooling system, driveline, axle ratios, software, and aftertreatment communication.

It should not be treated as a universal replacement transmission for unrelated engines or older International trucks.

Common Applications

  • Long-haul transportation
  • Regional hauling
  • Dedicated fleet operations
  • Dry van transportation
  • Refrigerated transportation
  • Tanker operations
  • Bulk transportation
  • Flatbed operations
  • Construction hauling
  • Dump truck operations
  • Paving operations
  • Heavy-haul transportation
  • Off-road vocational work
  • Municipal service
  • Utility operations
  • Vocational tractor applications
  • Equipment transportation
  • Aggregate hauling

Truck and Engine Compatibility

The T14 was designed specifically for the International S13 Integrated Powertrain. It is not a general-purpose transmission intended to be paired with the International A26, Cummins X15, or older International engines.

The primary engine pairing is:

The S13 is a 12.74-liter inline six-cylinder diesel available in ratings reaching 515 horsepower and 1,850 lb-ft.

Current International truck families offering the S13 and T14 include:

The LT is the principal highway and long-haul application. The RH supports regional and local tractor operations. The HX and HV expand the T14 into construction, dump, heavy-haul, paving, and other vocational work.

Compatibility must be verified using the truck model, VIN, engine rating, axle ratio, tire size, gross weight, PTO installation, body equipment, and operating application.

Advantages

  • Fourteen forward ratios provide a wide operating range
  • Two crawler gears improve loaded startability
  • Six reverse ratios improve maneuvering flexibility
  • Direct drive supports efficient highway operation
  • Overdrive provides additional cruising flexibility
  • Single-countershaft design reduces complexity
  • Planetary reverse reduces size and weight
  • Compact packaging leaves more chassis space
  • Electronically controlled shifts reduce driver workload
  • Integrated S13 controls improve shift coordination
  • Low engine-speed operation can improve fuel efficiency
  • Automated clutch operation eliminates the clutch pedal
  • Vocational operating modes are available
  • Factory-installed PTO options are available
  • Split-shaft and auxiliary-transmission support is available
  • Hill Hold reduces vehicle rollback
  • Downhill Speed Control supports descents
  • Eco-Coast can reduce fuel consumption when conditions permit

Limitations or Considerations

  • The T14 is limited primarily to the S13 Integrated Powertrain
  • It is not a universal replacement transmission
  • Electronic diagnosis requires International-compatible equipment
  • The dry clutch remains a wear component
  • Excessive creeping can overheat the clutch
  • Improper programming can reduce performance
  • PTO applications require careful specification
  • Not every operating feature is available on every truck
  • Replacement controllers may require VIN-specific programming
  • Low-speed response differs from a torque-converter automatic
  • Repairs may require specialized training and parts
  • The transmission is newer than many established competitors
  • Long-term used-market parts availability is still developing
  • Truck pages describing older LT or HX configurations may not list the newer S13 and T14 powertrain

Driver and Operator Experience

The T14 provides two-pedal operation with no conventional clutch pedal or manual shift lever.

In automatic mode, the transmission selects the starting gear and shift sequence according to vehicle weight, terrain, accelerator demand, and programming.

Drivers may notice that the S13 operates at lower engine speeds than many older heavy-duty engines. The transmission is designed to use the S13’s strong low-rpm torque rather than holding unnecessarily high engine speed.

The transmission can skip gears when the truck is lightly loaded. Under heavy loads, it can use additional ratios to maintain performance.

Maneuvering Mode can improve control during docking, coupling, body positioning, and vocational work. Drivers should still use gentle accelerator input because the transmission controls a mechanical dry clutch.

Hill Hold helps prevent rollback when starting on a grade. Downhill Speed Control coordinates the transmission, engine brake, and vehicle speed during descents.

Manual mode allows the driver to request a gear, but the transmission can reject a request that would place the engine or driveline outside approved limits.

Maintenance and Ownership Notes

The T14 must be serviced with International-approved 75W-80 transmission lubricant. Using the wrong fluid can cause poor shifting, internal wear, overheating, or transmission damage.

Lubricant capacity changes when transmission-mounted PTO equipment is installed. The correct fill quantity should be confirmed using current service information.

The clutch, actuator, transmission controller, wiring, connectors, cooler, lubricant lines, seals, and driveline connections should be included in preventive maintenance.

International service information indicates the transmission filter should be serviced at the prescribed fluid-change interval or time limit for the specific application.

Software updates can affect shift quality, drive modes, PTO behavior, Hill Hold, Eco-Coast, and other operating functions.

PTO-equipped trucks require inspection of the PTO housing, mounting bolts, seals, hydraulic pump, controls, interlocks, and programming.

Because the T14 is highly integrated, a transmission complaint may originate in the S13 engine controls, vehicle controller, electrical system, clutch actuator, sensor network, or programming rather than inside the gearbox.

Common Transmission Problems

Clutch Wear

Repeated starts, excessive backing, steep grades, overloading, and prolonged low-speed operation can shorten clutch life.

Clutch Overheating

Holding the truck on a grade with accelerator pressure or maneuvering continuously at very low speed can generate excessive clutch heat.

Harsh Engagement

Rough forward or reverse engagement may result from clutch wear, failed adaptation, actuator problems, software, driveline looseness, or engine-control faults.

Failure to Select Drive or Reverse

Electrical faults, low air pressure, controller problems, sensor failures, active interlocks, or clutch-actuator issues can prevent gear engagement.

Shift Hesitation

The transmission may delay a shift when it detects an unsuitable engine speed, conflicting sensor data, a clutch problem, or a protective operating condition.

Lubricant Leaks

Leaks may develop around seals, PTO openings, cooler connections, gaskets, or damaged housings.

Cooling Problems

Restricted coolant flow, damaged lines, low lubricant, or heavy low-speed operation can contribute to elevated transmission temperature.

Sensor and Wiring Faults

Damaged wiring, loose connectors, corrosion, poor grounds, or failed speed and position sensors can cause warning messages or improper shifting.

PTO Operation Problems

Incorrect programming, failed interlocks, incompatible equipment, wiring faults, or an improperly selected PTO can prevent engagement.

Software or Calibration Problems

Incorrect parameters can cause unsuitable starting gears, poor low-speed response, unexpected shifts, or improper vocational-mode operation.

Buying Considerations

  • Confirm that the truck has the S13 Integrated Powertrain.
  • Record the transmission model and serial number.
  • Verify the S13 horsepower and torque rating.
  • Review the truck’s axle ratio and tire size.
  • Confirm the vehicle’s GVWR and GCWR.
  • Determine whether the application is highway or vocational.
  • Check which drive modes are programmed.
  • Confirm whether Maneuvering Mode is enabled.
  • Determine whether Hill Hold and Downhill Speed Control are configured.
  • Identify all transmission-mounted or engine-mounted PTO equipment.
  • Verify PTO speed, direction, torque, and horsepower requirements.
  • Confirm whether split-shaft or auxiliary-transmission programming is needed.
  • Review clutch-wear and clutch-temperature history.
  • Scan all powertrain controllers for active and stored faults.
  • Inspect the transmission for leaks or impact damage.
  • Check electrical connectors, coolant lines, and lubricant lines.
  • Test automatic and manual shifting.
  • Test all reverse ratios under safe conditions.
  • Review fluid, filter, software, and repair records.
  • Confirm remaining warranty coverage.

Variants and Configurations

  • International T14 Highway Configuration
  • International T14 Regional-Haul Configuration
  • International T14 Vocational Configuration
  • International T14 Overdrive Configuration
  • International T14 with Single Transmission PTO
  • International T14 with Dual Transmission PTO
  • International T14 with Rear-Engine PTO
  • International T14 with Front-Engine PTO
  • International T14 Split-Shaft Configuration
  • International T14 Auxiliary-Transmission Configuration
  • T14 Paver Mode
  • T14 Off-Road Mode
  • T14 Maneuvering Mode
  • T14 Hill Hold Configuration
  • T14 Downhill Speed Control Configuration
  • T14 Auto Neutral Configuration

Comparison to Similar Equipment

Compared with the Eaton Cummins Endurant HD, both are lightweight automated manual transmissions designed for integrated engine communication and highway efficiency. The T14 is paired specifically with the International S13, while Endurant HD is paired primarily with Cummins engines.

Compared with the Eaton Cummins Endurant XD, the vocational T14 offers two crawler gears, six reverse ratios, and application-specific programming. Endurant XD supports a different group of engines and truck manufacturers.

Compared with the Detroit DT12, both are proprietary integrated automated manuals. The DT12 is paired with Detroit engines in Freightliner and Western Star trucks, while the T14 is paired with the International S13.

Compared with the Volvo I-Shift, both use integrated engine and transmission controls. The T14 is designed for International trucks, while I-Shift is centered on Volvo powertrains.

Compared with the Mack mDRIVE, the T14 has 14 forward ratios as standard, including two crawler gears. The highway mDRIVE commonly uses 12- or 13-speed configurations.

Compared with the Mack mDRIVE HD, both support vocational operation, crawler gearing, multiple reverse ratios, and specialized drive modes. The correct transmission depends on the manufacturer’s integrated powertrain.

Compared with a torque-converter automatic such as the Allison 3000 Series, the T14 offers a direct mechanical power path and highway-oriented efficiency. The Allison can provide smoother continuous torque multiplication during stop-and-go vocational work.

Best Fit For

  • International S13-powered trucks
  • Long-haul fleets
  • Regional-haul operations
  • Fuel-efficiency-focused carriers
  • International LT operators
  • International RH regional fleets
  • International HX vocational operations
  • International HV vocational fleets
  • Dump and construction applications
  • Paving operations
  • Fleets requiring crawler gears
  • Applications requiring several reverse speeds
  • PTO-equipped vocational trucks
  • Fleets seeking integrated two-pedal operation
  • Operators wanting one powertrain for highway and vocational configurations

Related Truck Types

Related Truck Models

Related Engines

Related Transmission Types

Related Equipment Systems

Related Guides

Understand the operating principles in How Commercial Truck Transmissions Work, compare drivetrain designs in Manual vs Automated Manual vs Automatic Transmissions, and evaluate gearing, application, and compatibility in How to Choose a Commercial Truck Transmission.

Regulatory and Compliance Notes

The T14 must be installed and programmed as part of an approved International S13 powertrain and vehicle configuration.

The transmission controller communicates with the engine, aftertreatment system, braking system, vehicle controller, instrument panel, and PTO equipment. Modifications must not disable required emissions, diagnostic, or safety functions.

Replacement controllers or transmissions may require VIN-specific programming and clutch calibration.

PTO and auxiliary-equipment installations must use properly rated equipment, approved mounting practices, guarding, controls, and safety interlocks.

The transmission’s torque rating does not establish the vehicle’s legal weight capacity. Operators must remain within the truck’s GVWR, GCWR, axle ratings, tire ratings, bridge-law limits, and permit requirements.

Real World Operating Notes

The T14’s wide ratio spread allows one basic transmission design to support both highway and vocational work.

In highway service, the transmission frequently aims to operate in 13th-gear direct drive when that provides the best efficiency. It uses 14th-gear overdrive when vehicle speed, terrain, load, and axle gearing make overdrive more suitable.

Drivers should expect the S13 to operate at lower engine speeds than many older diesel powertrains. Full torque is available at approximately 900 rpm on applicable ratings.

The crawler gears can improve control during heavy starts and low-speed vocational work. Drivers should still avoid unnecessarily slipping the clutch.

Six reverse ratios provide useful flexibility, but higher reverse speeds should be used cautiously and only in appropriate operating environments.

Proper application programming is essential. A long-haul LT, regional RH, dump-body HX, and paving-equipped HV require different operating priorities and may use different T14 settings.

Frequently Asked Questions

What is the International T14?

The T14 is a 14-speed automated manual transmission designed specifically for the International S13 Integrated Powertrain.

How many forward gears does it have?

It has 14 forward gears, including two crawler ratios.

How many reverse gears does it have?

The T14 provides six reverse ratios through its planetary gear system.

What is its first-gear ratio?

First gear is 20.81:1.

Is the T14 direct drive or overdrive?

It provides both. Thirteenth gear is direct at 1.00:1, and 14th is a 0.78:1 overdrive.

How much torque can it handle?

The T14 is paired with S13 ratings reaching 1,850 lb-ft.

Which engine works with the T14?

Its intended engine pairing is the International S13.

Can it be paired with an International A26?

The T14 was designed specifically for the S13 Integrated Powertrain. The A26 commonly uses other transmission families.

Which trucks use it?

It is available in the International LT Series, International RH, International HX Series, and International HV.

Does the T14 have a clutch pedal?

No. It uses an electronically controlled clutch and two-pedal operation.

Can the T14 operate a PTO?

Yes. Compatible configurations support single or dual transmission PTOs, REPTO, FEPTO, split-shaft operation, and auxiliary-transmission programming.

Is the T14 suitable for vocational work?

Yes. Vocational configurations include crawler gears and programming for paving, off-road operation, maneuvering, PTO equipment, and split-shaft applications.

Availability and Where to Find

New International T14 transmissions are available as part of compatible S13 Integrated Powertrain specifications through authorized International dealers.

The T14 is offered in compatible International LT, RH, HX, and HV trucks. Availability varies by truck model, engine rating, axle configuration, vocation, PTO equipment, and production year.

Replacement transmissions, clutches, actuators, controllers, PTO components, coolers, filters, and service parts may be available through International dealers, authorized remanufacturers, and commercial drivetrain suppliers.

A used transmission should be identified by its complete model and serial number. Buyers should verify compatibility with the truck’s VIN, S13 rating, electronics, axle ratio, PTO equipment, and intended application.

Replacement transmissions or controllers may require vehicle-specific programming, clutch calibration, and software setup after installation.

Current product information can be confirmed through International’s official S13 Integrated Powertrain page.

Technical programming and body-builder information is available through International’s T14 Transmission Resources.

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