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TES 668 Equivalent

TES 668 Equivalent

Automatic transmission fluids are the lifeblood of modern vehicles, playing a crucial role in ensuring smooth operations, enhancing fuel efficiency, and prolonging the lifespan of the transmission system.

As with any crucial component of an automobile, the quality, and type of fluid used can make a marked difference in performance and longevity. This is where the TES 668-approved fluids come into the picture.

After extensive research and personal experience, I wholeheartedly recommend Delo Syn ATF 668 as the superior choice for transmission fluid.

Its cutting-edge formula ensures not only better clutch friction control and wear protection but also guarantees smoother shifts across various speeds and temperatures.

Remarkably, even in the toughest of operating conditions, it effectively minimizes noise and vibrations. For those already using Allison-approved TES 295, TES 389, or TES 468 fluids, the transition to Delo Syn ATF 668 is seamless, thanks to its backward compatibility. Truly, it stands out as the best equivalent in the market.

Understanding TES 668-Approved Fluids

The TES 668 standard, endorsed by Allison Transmission, one of the foremost names in the realm of automatic transmissions, is not just another specification. It represents a rigorous testing and validation process designed to determine a fluid’s ability to meet the demanding requirements of modern automatic transmissions.

Whether it’s about reducing wear, ensuring optimal thermal stability, or maintaining fluidity in extreme conditions, a TES 668 certification is a testament to a fluid’s superior quality and performance.

These fluids have been engineered to build upon the legacy of TES 295® synthetic fluid. While TES 295® has been trusted by industries for over two decades, TES 668® incorporates a modern additive package that aligns with the evolving needs of transmission systems.

Hence, when one uses a TES 668-approved fluid, they’re not just opting for a product; they’re choosing a legacy of trust, performance, and innovation.

Benefits of Using TES 668-Approved Products

  1. Extended Drain Intervals: With these fluids, users can often extend the time between fluid changes, leading to reduced maintenance costs over the vehicle’s lifespan.
  2. Enhanced Performance: Designed for the high demands of automatic transmissions, these fluids ensure smoother gear shifts, optimal torque transfer, and reduced wear.
  3. Lower Operating Expenses: The superior thermal stability and wear protection mean fewer breakdowns, prolonged transmission life, and lower repair bills.
  4. Optimum Transmission Protection: With their advanced formulation, these fluids offer maximum protection against common transmission issues such as sludge formation, oxidation, and corrosion.
  5. Assurance of Quality: Every TES 668-approved product comes with the backing of the Allison Authorized Service Network and an Allison Factory Warranty, offering peace of mind to users.

TES 668 Equivalents

The realm of transmission fluids has seen an array of innovative products, particularly with the introduction of TES 668-approved fluids. This standard ensures that each product under its umbrella offers optimal performance, protection, and longevity.

Product NameApplication Number
DuraDrive™ HD Synthetic 668668-10012020
CHRYSAN SYN 668668-10022021
Castrol TranSynd™ 668668-10032020
Delo SYN ATF 668668-10042020
CITGO SynDurance® 668 Automatic Transmission Fluid668-10052021
Spirax S6 ATF A668668-10062021
SK HD 668 Fully Synthetic Automatic Transmission Fluid668-10072021
FLUIDMATIC SYN T668668-10082021
FUCHS TITAN ATF 5668668-10092021
Advantage ATF 668668-10102021
Valvoline Syn Gard™ 668 Automatic Transmission Fluid668-10112021
Sunoco Duratrans ATF 668668-10132021
Lubriguard Heavy Duty Synthetic 668 ATF668-10142021
Rugged 668 HD Synthetic Transmission Fluid668-10172021
Phillips 66 Triton® 668668-10182021
Kendall SHP® 668668-10192021
Mobil Delvac 1 ATF 668668-10202021
Spirax S6 ATF A668668-10222021
Emgard ATF 7668668-10242021
RAVENOL ATF THS Truck HD Synthetic668-10262022
RAVENOL ATF THS Truck HD Synthetic668-10272022
MAXTRON ATF SS8668-10282022
HD SYN DRIVE Full Synthetic Transmission Fluid668-10292022
Tutela ATF 900 HD-AXD668-10302022
PurTrax Heavy Duty Synthetic Automatic Transmission Fluid668-10312022
PurTrax Heavy Duty Synthetic Automatic Transmission Fluid668-10322023
Syn-TS HD668-10332023
PACCAR ATF All Duty On-Highway Transmission Fluid668-10362023
Delo SYN ATF 668668-10372023
Fleetrite ATF All Duty On-Highway Transmission Fluid668-10382023
Elixir Full Synthetic MAX-TORQUE Transmission Fluid668-10392023

Let’s delve deeper into some of these products to better understand their unique offerings:

Delo SYN ATF 668

  • Distinguishing Features: Delo stands out for its advanced anti-wear technology, which is particularly beneficial in preventing premature wear in high-torque applications.
  • Applications: Ideal for modern vehicles with sophisticated transmission systems.
  • Unique Selling Points: Extended fluid life, superior shift performance, and protection against sludge and deposit formation.

DuraDrive™ HD Synthetic 668

  • Key Features: Known for its synthetic blend, DuraDrive offers superior temperature stability, ensuring smoother transmission performance under varying conditions.
  • Applications: Suitable for heavy-duty applications, especially in commercial vehicles that require extended drain intervals.
  • Benefits: Offers extended transmission life, reduced maintenance costs, and improved fuel efficiency.


  • Overview: This fluid is recognized for its high-quality formulation, providing protection against wear and tear.
  • Formulation: CHRYSAN incorporates advanced additive technology that ensures optimal friction control and anti-shudder properties.
  • Usage Recommendations: Ideal for modern automatic transmissions requiring precise synchronization.

Castrol TranSynd™ 668

  • Market Reputation: Castrol, a globally recognized brand, has yet again proven its mettle with TranSynd, making it a popular choice among professionals.
  • Proprietary Formula: The unique blend offers enhanced resistance against oxidation and thermal degradation, ensuring longevity.

Common Features Among Approved Fluids

TES 668-approved fluids signify the highest standards of performance, protection, and longevity for automatic transmission systems.

While each brand and formulation brings its own set of unique features and benefits, there are certain commonalities that all these fluids share, a testament to their adherence to the stringent TES 668 standards. Let’s highlight these shared characteristics:

1. Fluid Stability

Every TES 668-approved fluid showcases a pronounced resistance to oxidation. This means that the fluid can withstand high temperatures without breaking down, ensuring that the fluid remains stable and efficient over extended periods of use.

2. Enhanced Lubrication

These fluids are formulated with advanced lubricating agents. As a result, they reduce friction between transmission components, which not only ensures smoother shifting but also minimizes wear and tear, thereby extending the lifespan of the transmission system.

3. Adaptability to Various Operating Conditions

Regardless of whether a vehicle is operating under extreme cold or in sweltering heat, TES 668-approved fluids are adept at maintaining their performance. They offer a high viscosity index, meaning they won’t thin out too much under high temperatures or become too thick under cold conditions, ensuring consistent performance.

4. Superior Protection

All TES 668-approved fluids offer robust protection against corrosion, rust, and the formation of sludge or deposits. This ensures that the internal components of the transmission remain clean and free from contaminants, leading to longer transmission life and reduced maintenance needs.

5. Extended Drain Intervals

One of the standout features of these fluids is the extended drain intervals they offer. With enhanced stability and resistance to degradation, users can benefit from longer periods between fluid changes, leading to cost savings and reduced downtime.

6. Broad Compatibility

Most of these fluids are designed to be compatible with a wide range of transmission types, from older models to the latest, sophisticated systems. This universality ensures that users don’t need to switch between different fluids for different vehicles.

Choosing the Best TES 668-Approved Fluid for Your Needs

Choosing the ideal transmission fluid, even from a list of top-tier, approved products, can feel daunting. However, with a clear understanding of selection criteria, end-users can navigate these choices with confidence. Here are some key tips and guidelines to help in making an informed decision:

1. Vehicle Compatibility

  • Always consult your vehicle’s manual first. While TES 668-approved fluids have broad compatibility, it’s essential to ensure the chosen product is explicitly recommended for your vehicle type and model.

2. Operational Environment

  • Temperature: If you regularly drive in extremely cold or hot conditions, choose a fluid known for its excellent performance in those specific temperatures.
  • Terrain: For vehicles frequently used on rugged terrains or carrying heavy loads, opt for a fluid with superior anti-wear properties.

3. Fluid Longevity and Drain Intervals

  • If you’re looking for reduced maintenance, prioritize fluids that offer extended drain intervals. While all TES 668 fluids offer this benefit, some might have longer intervals than others.

4. Brand Reputation

  • While all TES 668-approved fluids meet high standards, brand reputation can be a decisive factor. Brands with a longstanding history or particularly positive reviews might offer added assurance.

5. Additive Package

  • Delve into the fluid’s additive composition. Some additives can enhance anti-wear properties, oxidation stability, or corrosion resistance, which might be crucial for specific use cases.

6. Cost-effectiveness

  • While it’s not always advisable to go for the cheapest option, it’s essential to find a balance between cost and quality. Consider the fluid’s price in conjunction with its benefits, reviews, and brand reputation.

7. Availability

  • It’s practical to choose a product readily available in your region. This ensures ease of repurchase and might also mean better post-purchase support.

8. Environmental Impact

  • If sustainability is a priority for you, consider fluids that tout eco-friendly formulations or manufacturing processes.

9. Technical Support and Warranty

  • Brands that offer robust technical support can be invaluable for any queries or issues. Additionally, a good warranty signifies the brand’s trust in its product.

10. Personal Recommendations:

  • Sometimes, word-of-mouth can be the most trustworthy. If fellow vehicle owners or mechanics have had a positive experience with a particular fluid, it might be worth considering.

Historical Evolution of TES Fluids: From TES 295 to TES 668

For those in the automotive and commercial vehicle industries, the term “TES” is synonymous with quality, performance, and reliability.

As the industry evolved, so did the fluid technology that supported it. This is the story of the evolution of TES fluids, a journey from the pioneering TES 295® to the innovative TES 668®.

The Inception: TES 295

The late 20th century saw a remarkable transformation in the transportation and commercial vehicle sector. With vehicles becoming more sophisticated and demanding, there was a need for a transmission fluid that could handle these evolving challenges. Enter TES 295®.

Allison Transmission, recognizing the shift in industry demands, launched the TES 295®. This was not just another transmission fluid. It was a testament to meticulous research, advanced engineering, and a deep understanding of the transmission systems of the era.

Designed to offer extended drain intervals and enhanced transmission performance, TES 295® quickly became the gold standard in the industry. Its synthetic base ensured smoother operations, better temperature resistance, and overall longevity for the transmission systems.

Changing Times, Changing Needs

As the years passed, vehicles started becoming even more complex. The introduction of advanced electronics, hybrid systems, and intelligent transmission control units necessitated a new breed of transmission fluids.

The industry needed a fluid that was not only a lubricant but also a medium that could handle heat, reduce friction, and support the ever-increasing demands of modern transmission systems.

The Next Generation: TES 668

Building upon the legacy of TES 295®, Allison Transmission introduced the TES 668®. This was not merely an upgrade but a transformational change. The TES 668® came equipped with a modern additive package, ensuring it was attuned to the needs of the contemporary transmission systems.

The advancements in fluid technology were evident. TES 668® boasted of superior fluid stability, enhanced lubrication properties, and an exceptional performance in cold operations. The benefits weren’t just theoretical. They translated to extended drain intervals, optimized transmission protection, and lower operating costs for users.

The Rise of Numerous Approved Fluids

With the introduction and success of TES 668®, there was a surge in the market for transmission fluids aiming for this standard. Brands recognized the importance of aligning with the TES 668® specifications, leading to the rise of numerous approved fluids.

These ranged from globally recognized brands to niche specialists, each bringing their unique blend of technology and additives, but all adhering to the high standards set by TES 668®.

Safety and Usage Precautions: Navigating TES 668-Approved Fluids

Using TES 668-approved fluids can vastly improve the performance and longevity of your automatic transmission system. However, for maximum benefits and safety, certain precautions need to be observed.

Here’s a rundown of the dos and don’ts, coupled with insights on potential consequences and the necessity of regular maintenance.


  1. Read the Manual: Before adding or changing the fluid, always consult the vehicle’s owner manual. This will provide specifics on the amount and type of fluid needed.
  2. Store Properly: Keep the fluid container sealed tightly when not in use, stored in a cool, dry place away from direct sunlight.
  3. Use Clean Tools: Always ensure that funnels or any other tools used are clean to prevent contamination.
  4. Regular Maintenance: Schedule routine transmission checks to monitor fluid levels and condition. Change the fluid as recommended by the manufacturer.
  5. Dispose of Old Fluid Responsibly: Transmission fluids are hazardous to the environment. Use designated disposal facilities or recycling centers.


  1. Avoid Mixing Fluids: Never mix different brands or types of transmission fluid, even if they’re both TES 668-approved. They may have unique additive packages that can react adversely when combined.
  2. Don’t Overfill: Overfilling can lead to frothing, which can cause erratic shifting and potential damage.
  3. Avoid Contact with Skin: These fluids can be irritants. Wear gloves when handling and wash any spills on the skin immediately.
  4. Keep Away from Children: Ensure that the fluid containers are out of reach of children.

Consequences of Mixing Different Fluids

  • Chemical Reactions: Different fluids have unique additive compositions. Mixing them can cause unforeseen chemical reactions, leading to reduced effectiveness or even damage.
  • Viscosity Issues: Mixing fluids might lead to unexpected viscosity levels, affecting the smooth operation of the transmission.
  • Warranty Concerns: Mixing different fluids might void any warranties on the transmission.
  • Reduced Performance: Combining fluids can reduce the beneficial properties of each, leading to sub-optimal transmission performance.

Importance of Regular Maintenance Checks

  • Optimal Performance: Regular checks ensure that the fluid is in good condition and is maintaining its essential properties.
  • Early Problem Detection: Routine inspections can help identify issues like leaks or contaminants early on, potentially saving costly future repairs.
  • Extended Lifespan: By ensuring the fluid is always in its best state, the transmission’s lifespan can be significantly extended.

In summary, while TES 668-approved fluids offer stellar performance, safety, and usage precautions are paramount. Being diligent and attentive to the health of your transmission fluid can significantly impact the longevity and efficiency of your vehicle’s transmission system.


About Thomas Buck

Thomas is our expert in the field of motor oils and lubricants. He worked for more than 15 years at the dealer service station and has the vast practical experience, so he gladly agreed to be the editor and co-author of our articles about motors and motor oils.

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