Unraveling TES 668 Transmission Fluid Equivalents

Unraveling TES 668 Transmission Fluid Equivalents

When it comes to transmission fluid equivalents, three top contenders stand out in the heavy-duty automotive world: Castrol TranSynd 668, Transynd Full Synthetic Transmission Fluid, and Mobil Delvac Syn ATF. 

Castrol TranSynd 668 is renowned for its exceptional performance and is often considered a benchmark in the industry.

 Transynd Full Synthetic Transmission Fluid is another stellar choice, known for its durability and longevity. 

Finally, Mobil Delvac Syn ATF offers robust protection and reliability. Each of these options boasts excellent quality and is trusted by mechanics and truck owners alike, ensuring smooth and trouble-free transmissions.

What Is TES 668 Fluid?

TES 668 Fluid is a type of synthetic transmission fluid designed for on-highway automatic transmissions, specifically for use with Allison Transmissions.

It is an improved version of TES 295 fluid, offering similar excellent performance with updated additives.

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What Is Compatible With Transynd 668?

Castrol TranSynd 668 ALLISON

TES 668 Transmission Fluid Equivalents


  • Castrol TranSynd 668: Specifically designed for ALLISON transmissions.
  • Updated 2021 specification: Complies with the latest industry standards.
  • Case of 3: Convenient packaging for multiple applications.
  • Superior protection: Ensures smooth transmission operation.
  • Trusted brand: Castrol is known for high-quality lubricants.
  • Doxa Worldwide: A reliable source for automotive products.
TES 668 Transmission Fluid Equivalents

Transynd Full Synthetic Transmission Fluid

Unraveling TES 668 Transmission Fluid Equivalents


Provides exceptional protection against wear and friction, extending transmission life.

  • Maintains optimal viscosity for smooth shifting in all temperatures.
  • Reduces heat generation and minimizes oxidation for longer fluid life.
  • Excellent resistance to varnish and sludge buildup.
  • Compatible with a wide range of transmission types and brands.
  • Ideal for commercial vehicles, buses, and industrial equipment.
  • Helps improve fuel efficiency through reduced friction.
  • Lowers operating temperatures, reducing the risk of overheating.

Mobil Delvac Syn ATF

TES 668 Transmission Fluid Equivalents


  • Exceptional high-temperature stability
  • Superior protection against wear and tear
  • Enhanced oxidation resistance for extended fluid life
  • Smooth and precise shifting in automatic transmissions
  • Compatible with a wide range of vehicle makes and models
  • Excellent low-temperature flow properties for cold weather starts
  • Reduces friction for improved fuel efficiency
  • Ensures consistent performance under heavy loads

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Which Allison Transmission Fluids Are Compatible With Delo Syn Atf 668?

Allison Transmission Fluids that are compatible with Delo Syn ATF 668 include TES 468®1, TES 468®1, and TES 468®1.

Is TES 668 Compatible With TES 295?

Yes, TES 668 is compatible with TES 295, allowing for seamless integration and functionality between the two systems or components.

What Is The Difference Between Allison TES 295 And 668?

Here is a table summarizing the key differences between Allison TES 295 and TES 668 transmission fluid specifications:

AspectAllison TES 295Allison TES 668
Oxidative StabilityStandard performanceImproved
Anti-Wear PerformanceStandard performanceImproved
Friction ModifierStandard performanceImproved durability
Shift QualityStandardImproved
Noise, Vibration, andHigher as fluid agesReduced as fluid ages

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TES295 Replacing With TES 668 

When replacing Allison TES 295 transmission fluid with TES 668, it’s essential to follow the manufacturer’s recommendations and guidelines for your specific transmission and application.

Here are the general steps to consider:

  • Check Compatibility
  • Drain Old Fluid
  • Replace Filters
  • Fill with TES 668
  • Monitor Levels
  • Test and Inspect
  • Dispose of Old Fluid

Delo Syn Atf 668 Equivalent

Delo Syn ATF 668 is an automatic transmission fluid designed to meet the requirements of various Allison transmission specifications, including TES 295, TES 468, and TES 389.

It is formulated to provide the necessary performance and protection for Allison transmissions. 

Castrol Transynd 668 Equivalent

Castrol Transynd 668 Equivalent

Mobil Delvac Synthetic ATF is another synthetic automatic transmission fluid, often used in heavy-duty applications, including Allison transmissions.

Mobil Delvac ATF is designed to meet or exceed the requirements of Allison’s TES 295 specification.

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Navistar TES 668 Equivalent

The term “TES 668®/295®” suggests that a particular transmission fluid meets both the Navistar TES 668 and Allison TES 295 specifications.

This indicates that the fluid is suitable for use in transmissions that require either of these specifications

Can You Mix Transynd 668 And 295?

Yes, you can mix Transynd 668 and Transynd 295 transmission fluids. Transynd is a brand of synthetic transmission fluid developed by Allison Transmission, and both Transynd 668 and Transynd 295 are compatible with each other.

What Is Compatible With TES 668?

Allison TES 668 transmission fluid is compatible with other Allison transmission fluid specifications, including TES 389, TES 295, and TES 468.

This means that TES 668 can be used interchangeably with these other Allison transmission fluids.

What Is The Allison TES 668 Equivalent?

The Mobil Delvac 1™ ATF 668 is an equivalent transmission fluid that meets the Allison TES 668 specification.

This means that Mobil Delvac 1™ ATF 668 is designed to provide the same performance and quality standards as required by Allison for TES 668-compliant transmission fluids.

Can You Mix Transynd 668 And 295?

Yes, you can mix Transynd TES 668 and TES 295 transmission fluids. Both Transynd TES 668 and TES 295 are compatible with each other and with Allison transmissions that require these specifications.

Is Dexron 3 compatible with TranSynd?

Yes, Dexron III transmission fluid is generally compatible with TranSynd transmission fluid. 

Steps For Proper Transmission Fluid Replacement

YouTube video
  • Step 1: Lift the vehicle securely.
  • Step 2: Locate and remove the transmission fluid drain plug.
  • Step 3: Drain old fluid into a suitable container.
  • Step 4: Replace drain plug and tighten.
  • Step 5: Access the transmission filler tube.
  • Step 6: Add the recommended amount of new transmission fluid.
  • Step 7: Check fluid level and adjust if necessary.
  • Step 8: Lower the vehicle and test for proper operation.

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Frequently Aasked Question About TES 668 Transmission Fluid Equivalents

1. What Weight Is Transynd 668?

The weight of Transynd 668, a type of transmission fluid used in heavy-duty Allison transmissions, typically comes in 38.2 pounds containers or jugs.

2. When Did TES 668 Come Out?

TES 668, also known as DuraDrive HD Synthetic 668, was introduced as the factory fill in Allison automatic transmissions starting on January 1, 2021.

3. Is Allison TES 668 Backward Compatible?

Allison TES 668 transmission fluid is designed to be backward compatible with previous Allison transmission fluid specifications, including TES 295.


In conclusion, when it comes to TES 668 transmission fluid equivalents, it is crucial to follow the manufacturer’s recommendations and specifications for your specific vehicle.

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