2023 International MV Transmission Fluid & Service

Quick Answer

• Transmission Make/Model: Allison 2500 RDS (most common, verify with vehicle specifications)
• OEM Fluid Spec: Allison TES 668™ (supersedes TES 295 for new applications)
• Drain & Fill Capacity: Approximately 18-20 quarts (varies by pan size and application)
• Full Overhaul Capacity: Approximately 29 quarts (varies by pan size and application)
• Filter OEM Part Number: Verify with dealer or service manual (internal filter kit typically includes main and sump filters)
• Recommended Service Interval:
  • Normal Duty: 48 months or 160,000 miles (257,500 km) or 4,000 operating hours
  • Severe Duty/Towing: 24 months or 80,000 miles (128,750 km) or 2,000 operating hours

Fluid Type Explained

The 2023 International MV series, a popular choice for vocational applications, primarily utilizes Allison automatic transmissions, with the Allison 2500 RDS (Rugged Duty Series) being a very common fitment. These advanced automatic transmissions demand a specific type of fluid to ensure optimal performance, durability, and efficiency. The OEM fluid specification for newer Allison transmissions, including those found in the 2023 International MV, is Allison TES 668™.

Allison TES 668™ is a proprietary specification developed by Allison Transmission to meet the rigorous demands of their modern transmissions. This specification supersedes the older TES 295® for new applications and offers enhanced protection against wear, improved thermal stability, and extended drain intervals. Using an approved TES 668™ fluid is crucial for maintaining transmission warranty coverage and maximizing the lifespan of your transmission. While some older Allison transmissions might still be serviced with TES 295® fluid, always confirm the correct specification for your specific 2023 International MV with the vehicle's service manual or an authorized International dealer. Using fluids that do not meet the TES 668™ specification can lead to premature wear, increased operating temperatures, and potential transmission failure.

Service Procedure

Servicing the transmission fluid in your 2023 International MV typically involves either a drain and fill or a full fluid exchange. Each method has its pros and cons:

Drain & Fill

A drain and fill involves draining the fluid from the transmission pan and replacing it with new fluid. This method is simpler and less expensive than a full exchange. However, it only replaces a portion of the total transmission fluid, leaving some of the old fluid in the torque converter and other internal components. For an Allison 2500 RDS, a drain and fill typically replaces around 18-20 quarts of fluid, depending on the pan size.

Procedure (General Steps – Always Refer to Service Manual):

1. Warm the transmission to operating temperature.
2. Safely lift and support the vehicle.
3. Remove the transmission drain plug and allow the fluid to drain completely into a suitable container.
4. Remove the transmission pan (if applicable for filter replacement) and clean any debris from the pan and magnet.
5. Replace the internal transmission filter(s).
6. Reinstall the pan with a new gasket (if applicable) and torque to specified values.
7. Refill the transmission with the correct amount of Allison TES 668™ fluid through the dipstick tube or fill port.
8. Start the engine, cycle through all gears, and recheck the fluid level according to the manufacturer's procedure (typically with the engine running at operating temperature).

Full Fluid Exchange

A full fluid exchange, often performed using specialized equipment, flushes out nearly all of the old fluid from the entire transmission system, including the torque converter and cooler lines, and replaces it with new TES 668™ fluid. This method provides the most thorough fluid replacement and is generally recommended for optimal transmission health, especially when switching to a new fluid type or addressing neglect.

Procedure (Typically Performed by Professionals):

1. Connect a specialized fluid exchange machine to the transmission cooler lines.
2. The machine will pump new fluid into the transmission while simultaneously extracting old fluid, ensuring a near-total fluid replacement.
3. Monitor the fluid clarity until new, clean fluid is circulating.
4. Check and adjust fluid level as per manufacturer specifications.

For accurate fluid capacities and detailed instructions, always consult the official Allison Transmission service manual or your International MV owner's manual.

Service Interval

Adhering to the recommended service intervals is paramount for the longevity and reliable operation of your Allison transmission in the 2023 International MV. Allison Transmission provides comprehensive guidelines based on various operating conditions:

• Normal Duty Service Interval:

  • Fluid: 48 months or 160,000 miles (257,500 km) or 4,000 operating hours, whichever comes first.
  • Filter: Replace at the first 12 months or 25,000 miles (40,250 km) or 1,000 operating hours, then every 48 months or 160,000 miles (257,500 km) or 4,000 operating hours thereafter.

• Severe Duty / Towing Service Interval:

  • Fluid: 24 months or 80,000 miles (128,750 km) or 2,000 operating hours, whichever comes first.
  • Filter: Replace at the first 12 months or 25,000 miles (40,250 km) or 1,000 operating hours, then every 24 months or 80,000 miles (128,750 km) or 2,000 operating hours thereafter.

Severe Duty Conditions typically include:

• Frequent stop-and-go driving
• Heavy loads/towing at or near GVWR or GCWR
• Operating in extreme hot or cold climates
• Excessive idling
• Frequent short trips
• Off-road operation

It's always better to err on the side of caution and follow the severe duty schedule if your International MV is frequently used in demanding applications. Regular fluid and filter changes help remove wear particles, maintain fluid integrity, and prevent costly transmission repairs.

Common Transmission Problems (Allison 2500 RDS Generation)

While Allison transmissions are renowned for their durability, like any complex mechanical component, they can experience issues. For the generation of Allison 2500 RDS transmissions found in the 2023 International MV, some common problems or areas of concern to be aware of may include:

• Electronic Sensor Malfunctions: Modern Allison transmissions rely heavily on electronic sensors for various functions, including shift timing and fluid temperature monitoring. Faulty sensors can lead to erratic shifting,