What is the Honda ATF-Z1?
ATF-Z1 is Honda’s original automatic transmission fluid specification that was used in many Honda and Acura vehicles from the 1990s into the early 2000s. It is not the same as the modern DW-1 fluid, and the correct choice depends on your model and year.
Historical context and design
During the 1990s, Honda developed ATF-Z1 to meet the friction and wear characteristics required by its automatic transmissions. This specification was tailored to Honda gear sets, seals, and clutches, helping ensure smooth shifting and reliable operation in many early-generation Honda/Acura models. Over time, Honda introduced a newer specification, ATF-DW1, for many later transmissions with updated seals and friction profiles. Because Z-1 and DW-1 rely on different friction modifiers, mixing them can cause shifting problems or wear. Therefore, using the exact specification your vehicle requires remains essential.
Key points about ATF-Z1:
- Proprietary Honda specification used primarily on older Honda/Acura automatic transmissions.
- Not interchangeable with Dexron II/III fluids; using the wrong type can lead to improper shifting or wear.
- Gradually phased toward the DW-1 specification for newer transmissions, though some older models still call for Z-1.
- Always confirm the required spec from the owner’s manual, a service sticker, or a dealer source; do not guess.
In short, ATF-Z1 served a long period as Honda’s standard for many older automatics, but modern Hondas typically require ATF-DW1. If your car specifies Z-1, use Z-1; if it specifies DW-1, use DW-1.
Modern replacement and compatibility
For many contemporary Honda and Acura vehicles, ATF-DW1 is the recommended fluid. DW-1 is a distinct specification designed for newer transmissions and is not the same as Z-1. While some fluids marketed as DW-1 claim broader compatibility, always follow the exact specification listed in your owner's manual or by your dealer. Do not mix Z-1 and DW-1 in the same transmission unless the manual explicitly allows it.
To determine which fluid is appropriate for your vehicle, consider the following:
- Check the owner's manual or the transmission dipstick/label for the specified ATF type (Z-1, DW-1, or a note indicating Dexron compatibility).
- Identify the model year and, if possible, the transmission type, since some transmissions have different fluid requirements over time.
- Consult a Honda dealer or official service bulletins for confirmation by VIN, especially for older models where production changes occurred.
- Only use the defined fluid for your vehicle and perform a drain-and-fill or full flush as required by the service schedule; do not mix fluids.
Following these steps helps ensure you use the correct ATF for your Honda, preserving shifting quality and transmission longevity.
Practical considerations and maintenance tips
Availability and brand choices
ATF-Z1 remains available from some suppliers, but ATF-DW1 is far more common for newer vehicles. When purchasing, choose a reputable brand that explicitly meets the Z-1 or DW-1 specification as required by your vehicle, and avoid substitutes that do not list the exact spec.
Flushing and mixing cautions
Do not mix Z-1 and DW-1 in the same system unless the manual explicitly allows it. If cross-contamination is suspected, a professional transmission service (drain and fill or full flush) may be necessary to restore proper operation.
Summary
Honda ATF-Z1 is the original proprietary transmission fluid specification used in many 1990s-era Honda and Acura automatics. It is distinct from the modern ATF-DW1 fluid, which is now standard for many newer transmissions. Always use the exact specification specified for your vehicle, and avoid mixing different ATF types to protect transmission performance and longevity.
What ATF does Honda recommend?
Always use Honda ATF-Z1 (automatic transmission fluid).
Is the Honda ATF Z1 the same as Dw1?
ATF-DW1 is the updated, full synthetic replacement for the older ATF-Z1 fluid, and it can be used in any application that originally called for Z1. While you can mix DW-1 with Z1, it is best to drain and refill the system with DW-1 for a full changeover to get the benefits of the newer fluid. DW-1 is a backward-compatible successor that provides improved performance.
This video explains the differences between Honda's ATF-Z1 and ATF-DW1 and shows how to mix them: 1mClassic Gamers HQYouTube · Apr 15, 2012
ATF-DW1 vs. ATF-Z1
| Feature | ATF-Z1 | ATF-DW1 |
|---|---|---|
| Composition | Older, conventional formula | Newer, full synthetic formula |
| Compatibility | Primarily used in vehicles before 2011 | Replaces Z1 in all older vehicles and is the standard for newer models |
| Performance | Less advanced | Improved performance, especially in cold weather |
| Mixing | Should not be used in vehicles that call for DW-1 | Can be mixed with Z1, but a full fluid change is recommended |
| Application | Older Honda transmissions (non-CVT) | All Honda automatic transmissions (non-CVT) |
(this||self).Wufxzb=function(c,e,f,l,k){var d=document.getElementById(c);if(d&&(d.offsetWidth!==0||d.offsetHeight!==0)){c=d.querySelector("div");var g=c.scrollWidth-c.offsetWidth,h=Math.min(e?g:0,g);c.scrollLeft=e&&(l||f)?0:h;var a=d.getElementsByTagName("g-left-button")[0],b=d.getElementsByTagName("g-right-button")[0];a&&b&&(e=RegExp("\\btHT0l\\b"),f=RegExp("\\bpQXcHc\\b"),a.className=a.className.replace(e,""),b.className=b.className.replace(e,""),h===0?a.className="pQXcHc "+a.className:(a.className=
a.className.replace(f,""),k&&c.classList.add("pA30Ne")),h===g?b.className="pQXcHc "+b.className:(b.className=b.className.replace(f,""),k&&c.classList.add("FpCCub")),setTimeout(function(){a.className+=" tHT0l";b.className+=" tHT0l"},50))}};}).call(this);(function(){var id='_N-EladWYKr6O9u8Pv8LH4QI_359';var rtl=false;var gecko=false;var edge=false;var soh=false;
(this||self).Wufxzb(id,rtl,gecko,edge,soh);})();
Which fluid should you use?
- If your vehicle's owner's manual specifies ATF-Z1, you should use ATF-DW-1 instead.
- If your owner's manual specifies ATF-DW-1, you must use ATF-DW-1.
- Mixing the two fluids is acceptable, but it is best to perform a full drain and fill with DW-1 for the best performance and benefits.
This video explains how to perform a transmission fluid change in a Honda Civic: 50sTy MacWaltersYouTube · Jan 1, 2025
What is the Honda equivalent of ATF Z1?
The direct replacement for Honda ATF-Z1 is Honda ATF-DW1, which is the official successor and is backwards compatible. Other multi-vehicle or Honda-specific fluids from brands like Valvoline or RAVENOL can also be used, but check compatibility and follow a proper flush to remove the older fluid if necessary.
Official and recommended replacements
- Honda ATF-DW1: This is the official replacement for ATF-Z1 and is backwards compatible, meaning you can mix it with Z1 if you don't have enough for a full flush, though a complete drain and fill is recommended for best results. You can purchase this from a Honda dealership.
Other compatible fluids
- RAVENOL ATF Type Z1 Fluid: This is a direct equivalent, formulated for Honda transmissions.
- Valvoline MaxLife or Extended Protection ATF: Some users report successful use of these multi-vehicle fluids in Honda transmissions, including a 50/50 mix with DW-1.
- Castrol Import ATF: This is another over-the-counter fluid that is compatible with ATF-Z1.
Important considerations
- Flush old fluid: When switching from ATF-Z1, it is important to perform a transmission flush to remove as much of the old fluid as possible. A single drain and fill may not be enough.
- Check for other requirements: For vehicles with a CVT, ensure you are using the correct CVT fluid and not a standard ATF.
- Avoid certain fluids: Do not use newer Dexron formulas (like Dexron VI) as they are not backward compatible with the Z1 formula, according to AcuraLegend.Org.
What is ATF Z1?
ATF Z-1 is a fully synthetic automatic transmission fluid formulated to meet the demanding requirements of all HONDA and ACURA vehicles built with 4-5 speed automatic transmission systems, where ATF-Z1 fluid is required. Outstanding friction characteristics to improve the overall transmission durability.
PDF
