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Just found out that Honda recently discontinued ATF Z1 and replaced it with DW-1. Apparently the new transmissions (2011) can only use DW-1, but older ones can use either? Does anyone know what the difference is? I'm thinking of stocking up on Z1 before it runs out.

Also, if DW-1 is synthetic can I still do a drain and fill or do I have to flush and fill (which I really don't want to do)?
 

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DW-1 is compatible with and replaces Z1 in all non-cvt Honda transmissions. You can still do a drain and fill at the next recommended interval using DW1 instead of Z1.
 

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I'm thinking of stocking up on Z1 before it runs out.
Here is a little story if you don't mind... Last weekend while working on other things I checked the level of ATF in my tranny and it was below the MIN mark. I bought it used about 3 months ago and know little about the history of service for this van but I knew for a fact that they did dealer service (aka 'drain and refill') of tranny at about 15K km ago. Anyway, since there were no leaks visible anywhere so I am pretty sure they just under-filled it. I am also about 99% sure they used Z1 (the date of service was more than 1.5 years ago) but I only had DW-1 to top it up. Long story short, it took a little less than a quart and after driving it for about a week now I can feel a slight (positive) change in shifting. I am not sure whether it is because of the fact that I've added about 10% (1 qt out of ~8,5 qt total capacity, right?) of a 'new, fresh and synthetic' fluid or just because fluid is now at the appropriate level. However, also because I recently did a flush with DW-1 on my Civic and it made a world of difference I'd suggest to run away from Z1 even if someone gives it to you for free. Just my 2 cents... ;)
 

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I'm thinking the DW-1 is a superior product. My Honda part manager friend tells me they no longer carry Z1. Since he can get me the DW-1 cheaper than I can buy aftermarket synthetic, I will be using it on my next 4x drain/fill service. Encouraging to hear that you noticed an "improvement."


Regards,
Shea:)
 

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Considering that one cannot fully drain all ATF, are there any concerns with using the general 3x drain/fill rule, which ends up mixing new DW with old Z1? One may think that DW is degraded by mixing it with Z1.
 

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this may sound dumb, but how do you read the ATF dipstick? getting ready to roll out on a 1600 mile journey, and want to make sure
i am good on fluids, as i do have a small axle seal leak. Fluid was topped with DW1 about 3k ago.
 

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From owner's manual:

1. Park the vehicle on level ground. Start the engine, let it run until the radiator fan comes on, then shut off the engine. For accurate results, wait about 60 seconds (but no longer than 90 seconds) before doing step 2.

2. Remove the dipstick (yellow loop) from the transmission, and wipe it with a clean cloth.

3. Insert the dipstick all the way into the transmission securely as shown in the illustration.

4. Remove the dipstick, and check the fluid level. It should be between the upper and lower marks.

Question: if you didn't know how to check the level, how did you know how much to add for the top-off? Just curious.

OF
 

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I will be using it on my next 4x drain/fill service.Regards,
Shea:)
Considering that one cannot fully drain all ATF, are there any concerns with using the general 3x drain/fill rule, which ends up mixing new DW with old Z1?
Question from a long time lurker, but only my second post. Recently got our 3rd Odyssey, an '02 EXL with only 77k miles on it. Got it from a dealer, but it was traded in and don't know the AT fluid service history, so I know I should change it soon. I thought I read in the Owner's Manual that a true home mechanic total (or close to it) AT fluid "change" would be a total of 4x fluid changes. I think the manual states it as 3x change plus 1 last change for a total of 4x.

I've seen lots of mention of the 3x change, but Shea's post is one of the first I've seen that actually mentions 4x fluid change. Maybe being anal here, but want to change it as recommended per the manual and hopefully have the AT last as long as possible. What do you guys think?
 

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Owners manual says to do three drain and fills ( which according to the manual, each "change" takes 3.5 qts) and then do it a final fourth time. You are to drive it briefly between each change. This is all done to ensure you are getting all the fluid from the torque converter out of the transmission which holds a total of 8.3 qts (so you are only draining 3.5 qt each time then refilling and mixing with old stuff). After three , you pretty much have fully flushed out nearly all of the old fluid.

Or....use a transmission flush machine (we have a BG machine) which uses 16 qts and totally displaces and flushes the entire transmission (while running) .

Hope that helps.....oh and dealer wants about $6.50 per qt for the DW1 stuff here in Houston. At least its fully synth.
 

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Considering that one cannot fully drain all ATF, are there any concerns with using the general 3x drain/fill rule, which ends up mixing new DW with old Z1? One may think that DW is degraded by mixing it with Z1.
I had no problem mixing DW-1 with Z1; I did four drain/fills over a span of 1000 miles.
 

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Thanks Shriker, that's what I thought I read in the Owner's Manual. So it is actually a 4x drain/refill cycle to change it all out and will take approx. 14 qts. (4x3.5 qts.) to do it.
 

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Just found out that Honda recently discontinued ATF Z1 and replaced it with DW-1. Apparently the new transmissions (2011) can only use DW-1, but older ones can use either? Does anyone know what the difference is? ***snip***
DW-1 is also less viscous (flows easier). At the risk of mirroring the 5W-20/5W-30 debate, I decided to go Amsoil ATF instead of DW-1 because Amsoil matches the viscosity of Z1. (They also have an ATF that matches the viscosity of DW-1. It's called "fuel efficient" ATF.) In any case, DW-1 is far superior to Z1 if you want to stay OEM.
 

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I just changed mine today with DW-1 and I noticed that the drain plug magnet was covered in metal particles. I also noted that the colour of the fluid is really purple / pinkish. Weird colour. Seems smoother but not quite at the level of Amsoil, although it could be my imagination.
 

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I'll be doing the second full 4x drain/fill with the DW-1 next month.

I'd like to add, in a year's worth of driving, there IS a noticeable improvement in shift quality over using the Z1. :)

Also, those who were asking earlier- doing the repeated drain/fill sequence DOES make a difference in what's in there for fluid. I used separate containers to drain fluid into for each "cycle" the last time I did the 4x drain/fill on my parent's CRV-result was noticeably cleaner fluid at each step. :)

I drive my vehicles 20km's (12miles?) in between drain and fill procedures. All highway. Yes, that's 60km's total... Actually takes longer doing the driving part than the drain and fill part! :D

Don't have any fears using the DW-1 to replace Z1-it's compatible and a superior product.

Regards,
Shea:)

EDIT: REPLY TO ABOVE POST: Yeah, that purplie colour is wierd... took me off guard the first time I poured it, too. :)
 

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One thing that seems weird to me - why does Honda say to check fluid with car off? To me, don't you want it to be at the full mark when running? Logically, it would seem like if it isn't, then it wouldn't have enough fluid.
 

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One thing that seems weird to me - why does Honda say to check fluid with car off? To me, don't you want it to be at the full mark when running? Logically, it would seem like if it isn't, then it wouldn't have enough fluid.
Honda automatics have been this way for at least 20-25 years; their transmission design differs from the typical American car automatics on which the engine must be running when checking the fluid.
 
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