Honda Clarity Transmission Fluid Change

I change the transmission fluid in my Clarity Plug In every second oil change. So roughly every 15k miles I change it. It is fairly easy to do. Remove the 17mm fill plug. Remove the drain plug using a 3/8 socket wrench. Allow all the fluid to drain out. Change the crush gaskets on both the drain and fill plugs. Reinstall the drain plug. Pump fluid into the fill hole until fluid leaks out. You can buy a hand pump that threads right onto the bottle of Honda DW-1 Fluid. You will need three quarts of fluid but it will only take a bit over two quarts to fill it. The total you need according to Honda is 2.23 quarts. Reinstall the fill plug and you are done. On a lift I can do it in about 15 minutes. I do it more often than recommended because it is cheap and easy to do. Since it holds such as small amount of fluid I believe changing it more often is good idea. I have 102k miles on my Clarity now and so far no issues with the drivetrain.

Edit: I don't use the fill plug that the person in the video in post #11 does. On the drivers side of the transmission there is a 17mm bolt that you can remove to fill the transmission by pumping the fluid up into it. Once it is full it will start to run out like filling a differential. This is the way Honda recommends doing it as well. I work for a Honda dealer but I am not a technician. I attached a photo from Honda showing how it is suppose to be done. I am not saying you can't fill it the way the video shows in post #11. That will work as well but I would recommend you remove the drain plug to get all the fluid out. Then be sure to only fill it with the proper amount. You don't want to overfill it. Doing it the way Honda recommends you can't overfill since it comes pouring out once it is full.
 

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Alex800st said:
a bit overkill, no?
Interesting that on the diagram it says “Non-Honda ATF will affect shift quality” - it is just a gearbox, no shifting there.
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I agree, maybe a little excessive... Although there is no 'shifting', there is a multiple disk wet clutch inside that is used for 'engine drive' mode. A wet clutch could be subject to the particular characteristics of the fluid that is used.

My philosophy is that there is that there is nothing to be gained by using non-Honda fluid. If if is just cost that motivates you, it uses so little fluid and so infrequently that any cost savings will be trivial. Sticking with the manufacturer recommendations just seems prudent to me.
 
Alex800st said:
a bit overkill, no?

Interesting that on the diagram it says “Non-Honda ATF will affect shift quality” - it is just a gearbox, no shifting there.
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It probably is overkill but the cost and time to do it is minimal so that is what I'm doing. The fact it holds such a small amount of fluid is my reasoning. I drive a lot and already broke 100k miles. I imagine there aren't a lot of these on the road with high mileage yet. I don't know what to expect in terms of long term reliability. I figured changing the fluid more often can't hurt and even might help. Again, for the small expense and time involved I don't mind doing it.
 
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Just a reminder that the earliest recommended and most frequent interval for a transmission fluid change for the Clarity PHEV is 47,500 miles or 3 years. While the process is straightforward and relatively inexpensive as a DIY project, each time the system is open is an invitation for contaminants to enter the system.
 
Casey Martin said:
...I attached a photo from Honda showing how it is suppose to be done. I am not saying you can't fill it the way the video shows in post #11. That will work as well but I would recommend you remove the drain plug to get all the fluid out. Then be sure to only fill it with the proper amount. You don't want to overfill it. Doing it the way Honda recommends you can't overfill since it comes pouring out once it is full.
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One piece of advice [from me, an old airplane mechanic], Always loosen the fill plug first, before you remove the drain plug. That way, if the fill plug is stuck and can't be easily opened, you haven't drained your transmission. In this case, not a tragedy (because we have both a fill and overflow hole, and we know the approximate amount to add) but still I'd always remove the overflow first...
 
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JustAnotherPoorDriver said:
One piece of advice [from me, an old airplane mechanic], Always loosen the fill plug first, before you remove the drain plug. That way, if the fill plug is stuck and can't be easily opened, you haven't drained your transmission. In this case, not a tragedy (because we have both a fill and overflow hole, and we know the approximate amount to add) but still I'd always remove the overflow first...
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I agree 100%! Which is why I said to remove the fill plug first. ;)
 
Does our car has a tranny oil cooler? If it does, then a hack to change the oil would be to disco the hoses to the cooler to fill and drain.
 
Did Honda change the transmission fluid? I called my dealer and according to the VIN, the Honda Clarity no longer uses the DW-1 fluid. Instead, it uses their new CVT fluid at $35/L. Both dealers also said I need about 5L and not 2.11L as stated in the manual.
 
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geokilla said:
Did Honda change the transmission fluid? I called my dealer and according to the VIN, the Honda Clarity no longer uses the DW-1 fluid. Instead, it uses their new CVT fluid at $35/L. Both dealers also said I need about 5L and not 2.11L as stated in the manual.
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See these other threads:
https://www.insideevsforum.com/comm...ssion-fluid-change-much-less-than-spec.19312/
https://www.insideevsforum.com/community/index.php?threads/transmission-fluid-dw-1-vs-hcf2.19261/
https://www.insideevsforum.com/comm...luid-capacity—actual-experience-please.18566/

I think there has been enough experience here to say that the 2.11Q is correct for a drain / refill. I don't know where the 5L came from, but there was another forum member (in the 2nd link) who was charged for 5 qt. of HCF2 by his dealer when they changed his fluid, and he was questioning it both because of the amount, and also because it was not DW-1 as specified in the owner's manual.

BUT - Here's the thing though...
When you drain the fluid, and re-fill it, it only takes 2.11Q, but the transmission actually holds holds more than 3.3Q. I would not think that it's a good idea to mix two different types of fluid, therefore if Honda really did change from DW-1 to HFC2, then perhaps they have a way to drain the transmission more fully. Then. maybe it would take more then 2.11Q which makes it closer to 5Q.

If it were me, I would not trust a dealer citing what is appropriate for a given VIN unless they could provide a document that specifically states in writing that Honda has changed the fluid used in the Clarity from DW-1 to HFC2 or similar. At least this would rule out a possible error in their database and demonstrate that there really was an intentional change. It bothers me if a dealer is saying something that differs from the owner's manual without such a document to back it up.
 
geokilla said:
Did Honda change the transmission fluid? I called my dealer and according to the VIN, the Honda Clarity no longer uses the DW-1 fluid. Instead, it uses their new CVT fluid at $35/L. Both dealers also said I need about 5L and not 2.11L as stated in the manual.
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I don't think so. The tip looked the same as with the rest of the plug
 
There is a newer Honda transmission fluid for hybrid electric vehicles: HEVF Type 1.0 e-CVT fluid. Perhaps this is what the dealer is speaking about. You can find it on the College Hills Honda website:

https://www.collegehillshonda.com/product/08200-9022.html

where the cost is just over $3 a quart more than DW-1 fluid.

That webpage does say to "refer to your owner's manual" for vehicle applications. I plan to stay with DW-1 for my next transmission fluid change unless DW-1 is not available and replaced by the e-CVT fluid. BTW, when I changed the transmission fluid on our 2018 Clarity earlier this year, only 2.0 quarts drained out. So, I just put back in 2 quarts. In six years when the mm says to change the transmission fluid again, I will see if 2 quarts drain out. If less, I will assume that there is a leak.

LeoP
 
I'm also staying with DW-1. I just ordered four quarts to stash in my garage -- it'll probably be time for my fluid change later this year.
 
Checked with my Honda salesperson (family has known him for like 25 years) who checked directly with technician instead of parts. Honda DW-1 is the correct transmission fluid to use. It was parts that was making mistakes.

Now the only question is, do I want to use Honda DW-1 or Valvoline MaxLife? Theoretically Valvoline is a lot better but probably not a good idea to mix fluids?
 
geokilla said:
Now the only question is, do I want to use Honda DW-1 or Valvoline MaxLife? Theoretically Valvoline is a lot better but probably not a good idea to mix fluids?
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My non-professional opinion is to use the fluid recommended by the manufacturer (DW-1) for two reasons...

First, since it is not really possible to completely drain all the fluid, you will be mixing the two fluid types whether you intend to or not. We have no idea whether these two fluids are compatible with each other. It seems like the only way to minimize potential cross-contamination would be to drain, re-fill, drive some, then repeat this process a few times in order to dilute the old fluid until it is virtually gone. This seems wasteful and unnecessary.

Second, this transmission has components that are 'unique' including the electric motor / generator and wet clutches that are in contact with the fluid. I would not trust that any other random transmission fluid would be compatible with these unique components.

Why would you think that something else would be 'better' than what was originally chosen by the designers? Selecting something different seems to have multiple risks and no advantages.
 
MrFixit said:
Why would you think that something else would be 'better' than what was originally chosen by the designers? Selecting something different seems to have multiple risks and no advantages.
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Careful with bestowing goodwill and pure motives on the OEM's, MrFixit! While the engineering documentation "may" have specified a particular fluid for performance reasons, it is more likely either the base fluid that was available in the lab/shop during engineering development, or a basic requirements specification was provided to the purchasing department who then awarded the contract to the vendor who offered the lowest price/best terms/most exotic entertainment perks, depending on the purchasing mgr/agent's priority leanings. Cynical? yes, but have seen exactly that play out numerous times in automotive OEM's and Tier 1's as well as in the aerospace industry.

It is far more often, "cheapest that meets these minimum specs" than "Best available."

As a somewhat related example, one of my lads let his 2007 F-150 5.4L run a little low on engine oil, got severe misfires and all but total stalling once up to operating temperature and submitted it to his nearby Ford dealer for sorting. Amongst their estimate of about $16k in needed repairs was "replace engine" with notations that application of the new and improved variable valve timing solenoids "may" help but they didn't recommend as the truck wasn't quite producing the minimum oil pressure with which the new solenoids were developed. Poor lad was heavy-hearted and crestfallen, "I guess I need to get rid of it, but I can't even do that as it's registered in mom's name." I advised him to have it towed out to his boyhood abode and let the old man have a crack at it:

A 15 minute oil and filter change utilizing 15w-40 motor oil (I had recently switched the fleet from 5w-40 syn due to lack of reliable local availability of a version that met dual diesel/petrol specs) in lieu of Ford's Recommended 5w-20 and the truck ran flawlessly and produced normal oil pressure at and above idle, both cold and at operating temp. So....does Ford insist on 5w-20 because it is "Best?" One could argue for their purposes, "yes" as it will deliver better fuel mileage without any adverse effect on warranty costs. Is it "best" for the owner of a decade+ old used truck with over 200k on the odometer and a pre-occupation with studies for his master's degree, new job, and starting a family over exacting maintenance schedules? Hardly.

Having said all that, as a VVV stockholder, I'd like to applaud the member who wants to switch to Valvoline and encourage others to do likewise! Full disclosure.
 
AHolbro1 said:
Careful with bestowing goodwill and pure motives on the OEM's, MrFixit!
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AHolbro1 said:
Having said all that, as a VVV stockholder, I'd like to applaud the member who wants to switch to Valvoline and encourage others to do likewise! Full disclosure.
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Yikes !!
Let me rephrase my previous thought...
  • We know that DW-1 is at least 'compatible' with the Clarity transmission.
  • With anything else, we don't know whether it is compatible (particularly if it is mixed with the residual DW-1).
  • If we don't even know that it is compatible, then how could we possibly judge that it might somehow be 'superior'?
Well, maybe as a VVV stockholder it might be 'superior' to your pocketbook, but even if you could persuade every Clarity owner to switch, I don't think your stock value would even notice :p
 
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