Honda Clarity Transmission Fluid Change

[leop]

Honda specifies DW-1 transmission fluid for the Clarity PHEV. This the same fluid is specified for the Honda non-CVT automatic transmissions since well before the turn of the century. Honda automatic transmissions differ from just about all others. Most older automatic transmissions use planetary gears and bands. Honda automatic transmissions have gear clusters like manual transmissions with disc clutches instead of syncro cones and engagement teeth. DW-1 is party formulated to work with these wet disc clutches. The Clarity PHEV has a similar wet clutch to engage the direct drive mode. I suspect that is why the Clarity uses DW-1. Honda does have a new transmission fluid for its pure EV cars. These cars do not have wet disc clutches as there are no uses for such. This fluid is not specified foe the Clarity PHEV.

Using any regular automatic transmission in a Honda automatic transmission is not a good idea, especially for the CVT transmissions for which honda has a CVT fluid. I think that the Honda engineers know what they are doing and the transmission fluid specification is not at all based on cost considerations.

LeoP

 

[NorCalPete]

I often use alternative fluids versus the manufacturer's over-priced versions (e.g., engine oil, brake fluid, etc.), but sometimes it's best to stick with what they specify.

For example, I had to replace a worn out water-seal on my 1981 Honda GL500i (Silverwing) motorcycle, which required removing and partially disassembling the engine (a time-consuming job). I used Prestone coolant versus Honda's brand. Big mistake! The water seal lasted barely one month before it started leaking again. Turned out the seal only was compatible with Honda's coolant; anything else led to a quick failure. After flushing out the coolant system (and replacing the seal, again), it lasted for years with Honda's coolant.

As noted by @leop, ATF formulations can be tricky, hence my sticking with Honda's DW-1.

 

[Alex800st]

Every time I go to a local Honda dealer for the transmission fluid, parts guy checks his computer and gives me 5 bottles of HCF-2. Every time I question him on that, he disappears for 20-30 minutes, comes back with "sorry, I doublechecked" and 3 bottles of DW-1. Must be something in the Honda system that confuses them.

 

[megreyhair]

Every time I go to a local Honda dealer for the transmission fluid, parts guy checks his computer and gives me 5 bottles of HCF-2. Every time I question him on that, he disappears for 20-30 minutes, comes back with "sorry, I doublechecked" and 3 bottles of DW-1. Must be something in the Honda system that confuses them.

He probably didn't check and thought it uses HCF-2. If he did check, he would have known that it uses DW-1 and about 2 bottles and not 5 of HCF-2

 

[Joe17]

Another option to pumping into fill port is to remove the fill port and use a funnel to pour fluid into the top, where the rubber plug is, until fluid comes out of the fill port.

 

[Landshark]

For example, I had to replace a worn out water-seal on my 1981 Honda GL500i (Silverwing) motorcycle, which required removing and partially disassembling the engine (a time-consuming job). I used Prestone coolant versus Honda's brand. Big mistake! The water seal lasted barely one month before it started leaking again. Turned out the seal only was compatible with Honda's coolant; anything else led to a quick failure. After flushing out the coolant system (and replacing the seal, again), it lasted for years with Honda's coolant.

Non compatible coolants can cause significant damage. You’re fortunate to have had such a quick failure and to have identified the cause.

 

[Jose Gantes]

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.

Casey, does the 17 mm fill/overflow bolt have a crush washer that needs to be replaced? If yes do you happen to know the part number? I checked multiple Honda genuine parts websites and I could not find this 17 mm bolt in any of the Honda Clarity parts diagrams.

 

[Alex800st]

He probably didn't check and thought it uses HCF-2. If he did check, he would have known that it uses DW-1 and about 2 bottles and not 5 of HCF-2

mystery solved. I was at the same dealership and asked the guy to show me how he selects one fluid over another. On his computer he goes to Clarity, select Transmission and there is only one option that says “CVT” - so they go with their default cvt fluid. However if he goes to another system that requires to enter VIN - he will get a document that says dw-1 and short explanation why.

 

[NorCalPete]

...However if he goes to another system that requires to enter VIN - he will get a document that says dw-1 and short explanation why.

Did you see (and can summarize) that short explanation? That info might be helpful for those who had CVT fluid used by mistake.

 

[Alex800st]

Did you see (and can summarize) that short explanation? That info might be helpful for those who had CVT fluid used by mistake.

next time will make a picture.
It made me think- if I bring my car there for transmission flush - mechanic most likely will just request transmission fluid from parts department and unlikely check in the system - and just put a wrong one. However in the invoice it would say which one they used. If someone did it at the dealership- did you check your invoice?

 

[NorCalPete]

Mistakes like this are why I prefer to do my own car maintenance/repairs -- I know the job will be done correctly (and at a much lower cost). So far, our Clarity hasn't needed any dealership repairs, although I'll have to use them for the fuel pump impeller recall. I'll probably delay that repair for a while so the dealership can learn how to do it on other people's cars first.

 

[Alex800st]

Casey, does the 17 mm fill/overflow bolt have a crush washer that needs to be replaced? If yes do you happen to know the part number? I checked multiple Honda genuine parts websites and I could not find this 17 mm bolt in any of the Honda Clarity parts diagrams.

I just got both crush washers yesterday- here they are:

 

[insightman]

View attachment 23367
I just got both crush washers yesterday- here they are:

Did you mean to show us the crush washers? I'm curious why one costs so much more than the other.

 

[Alex800st]

Did you mean to show us the crush washers? I'm curious why one costs so much more than the other.

yes, someone asked for part n.
One cost so much more most likely because one is slightly bigger, or maybe because it’s Honda, and they just assign such small costs using random numbers generator.
In fact, I just finished the flush, and discovered that my car had both washers of the same size. They are quite close in size, and two bigger ones will work as well.

 

[Joe17]

Just changed my transmission fluid for the first time, 2018 with 53k, and it went easier than expected. The old oil was on the reddish brown side and it took right at about 2.25qts.

 

[TC1782]

Just changed my transmission fluid for the first time, 2018 with 53k, and it went easier than expected. The old oil was on the reddish brown side and it took right at about 2.25qts.

Curious, do you by chance have a picture of the used fluid? My transmission fluid when I changed it was pitch black (almost looked like oil that hadn't been changed soon enough). Basically only thing that would make the fluid black would be clutch material, did you do most of your traveling in EV mode? I wonder if the multi plate clutches will be a failure point on our cars, I know in China immd vehicles have had shift solenoid and clutch problems, not sure why their transaxles would be significantly different. In theory because IMMD synchronizes engine speed, and does a good job of handling over torque, there really shouldn't be any significant clutch wear. Attached are some materials detailing the multi plate clutch.

 

[Joe17]

No pics, but it was just a reddish brown....

 

[MrFixit]

My transmission fluid when I changed it was pitch black (almost looked like oil that hadn't been changed soon enough).

I just changed the transmission fluid today (2018 with 44K miles). The procedure I used was as follows:

1. Removed the 'check level' plug just to see whether the original fluid was at or above the check plug. No fluid came out.
2. Removed the drain plug and captured the fluid in order to measure how much drained out. 2.19 Quarts drained out.
3. Installed the drain plug and began filling through the access hole (with the rubber stopper) in the front. I added 2 quarts, then very cautiously started adding more oil until I saw it coming out of the 'check hole'. The total amount of oil I added was 2.25 quarts

Conclusions - The amount of oil that drained was as expected. The amount of oil I had to add was also as expected so the original oil fill was proper and none had been lost in the 6 years since purchase.

@TC1782 indicated that his oil was "pitch black". Although the old oil was definitely dark, I would not have characterized it as 'pitch black' . When it is sitting in the drain pan, it does appear black, but it is definitely a deep dark red (you can see this looking at the stream while it is draining). Nonetheless, I would say that the factory maintenance minder at 6 years seems like a reasonable time for a change.

 

[Casey Martin]

The fluid being "pitch black" or a "deep dark red" is the reason I change mine every second oil change. My transmission fluid comes out the same color as new fluid.

Is changing the fluid as often as I do necessary to extend the life of the transmission? I don't think anyone here can answer that. With that said changing the transmission fluid, if you work on your Clarity yourself, is not very expensive and fairly easy to do. Buying a pump that threads onto the large opening the newest DW-1 fluid quart uses or getting a pump/container that you can pour the fluid into is essential for this job to be easy. I change the crush gaskets every time I change the fluid for both the fill and drain plugs. I imagine you could reuse them a couple of times before they become too "crushed" but I replace them to be safe.

Anyway, I am going to continue changing the transmission fluid every second oil change with my Clarity PI. I am at 145k+ miles now and it is still going strong. I am hoping I can get easily over 200k miles. There are no new PI Hondas coming in the near future. I have worked for Honda for 30+ years and I will only drive a Honda/Acura for most of my vehicles. I am hoping Honda will release a PI CR-V but as of now that is not in the plans. As far as I am aware.

 

[TC1782]

The fluid being "pitch black" or a "deep dark red" is the reason I change mine every second oil change. My transmission fluid comes out the same color as new fluid.

Is changing the fluid as often as I do necessary to extend the life of the transmission? I don't think anyone here can answer that. With that said changing the transmission fluid, if you work on your Clarity yourself, is not very expensive and fairly easy to do. Buying a pump that threads onto the large opening the newest DW-1 fluid quart uses or getting a pump/container that you can pour the fluid into is essential for this job to be easy. I change the crush gaskets every time I change the fluid for both the fill and drain plugs. I imagine you could reuse them a couple of times before they become too "crushed" but I replace them to be safe.

Anyway, I am going to continue changing the transmission fluid every second oil change with my Clarity PI. I am at 145k+ miles now and it is still going strong. I am hoping I can get easily over 200k miles. There are no new PI Hondas coming in the near future. I have worked for Honda for 30+ years and I will only drive a Honda/Acura for most of my vehicles. I am hoping Honda will release a PI CR-V but as of now that is not in the plans. As far as I am aware.

Well, it certainly couldn't hurt, your probably on the right track. If my transmission doesn't blow up before 100K I will be changing it for a 2nd time then. I would change it sooner because of how black the fluid was when I changed it the first time, but I would rather have the transmission kill itself under warranty.