At 60,000 mi on my 2016 RDX, I decided to do a transmission flush and upgrade the filter. I decided to flush vs drain and fill because I switched over to Castrol Full Synthetic Multi-Vehicle ATF not to be confused with Castrol Import blend.

I replaced the inline filter with a Magnafine filter which is bigger and has a good size magnet too. I was pleasantly pleased to see that it fit in the factory filter holder. I left the lower hose off so I could attached a drain line to the bottom of the filter. In hindsight I would have installed an adapter to the top filter hose and drain from that but only had a hose no adapter. I ran the engine till flow slowed down and I could hear some suction from the pan then shut it down and filled the pan back up. I did this about 3-4 times and pulled out 12 qts total.

The fluid was still red before changing so it was hard to tell when all the old fluid was out. QUESTION- Was the fluid coming out of the filter coming from the cooler which was coming from the torque converter? I hope the fluid coming out wasn’t from the drain pan and I just wasted a lot of new fluid. Lol.

 

The method you used is not recommended by Honda for their transmissions. This is the flush method Honda approves and does is outlined in the service bulletin on transmission judder:
http://www.urvi.net/forumfiles/SB/B17-017.PDF
You must drive between normal drain & fills to get fluid out of the trans. Really drive, like going through all gears. Honda automatics are not like any other. Here is why:
https://global.honda/heritage/episod...ondamatic.html

If this fluid is actually compatible with Honda atf DW-1 I'm not sure why you feel
it is so important to try and replace all the fluid. By the way, with a Honda trans, that is not possible. (well, four drain & fills with driving in between would get you substantially there)
At 60k, you should have had a least one normal drain & fill at 30k.

 

I agree with egads above. The flush method will put undue pressure on seals and "might" cause problems now or in the future. As for the transmission fluid. Castrol does claim that their fluid is ATF-Z1, ATF-DW-1 compatable (as does other brands). Quite often people who change to this or similar after market brand fluid will notice a shifting difference when driving (more slippage or less slippage). Sorry, but my suggestion would be to go back to stock Honda fluid. These modifications you made (I realize you were trying to better your transmission) could cause more problems in the long run. If it were may car, I would just start doing a transmission drain and fill with the correct Honda fluid at each oil change and after about 4 drain and fills, you can stop. I would also remove the Magnafine filter and put things back to stock.

 

The Magnafine filter is probably fine, lots of Honda owners have added them to transmissions that came with no accessible filter at all.
I wonder what issue was trying to be addressed with this fluid change. I often laugh when folks report how much better their trans is with X fluid,
when just changing it is probably what made the biggest difference. When the original trans was made for a Honda V-6 the fluid change interval
was 45k. Now it is 30k. The exception is if one is experiencing the torque converter judder when Honda/Acura will do a 3X fluid change along with
a software update. I do think every oil change is maybe a bit extreme. But every other oil change is probably prudent. What fluid? Well we have a
thread on here about that. In that thread I posted a link to a thread on the Odyclub. In that thread is a link to a chemical analysis of the three most
popular compatible fluids. Interesting reading. The gist of that is that they are all very close.

 

Thanks for the info and feedback. Guess I'll refrain from the full flush next time. LOL. The dealer did do a 3X flush and software upgrade at 40,000 when I bought it as an off lease. It had that signature judder/jerky shifting. It went away after that service but I know the fluid is part to blame, so that's why I wanted a full synthetic alternative. At 60,000 I figured I would switch to Castrol since DW1 compatibility is listed. I contact the company and the engineer said that I should try to replace as much of the DW1 as possible when converting to Castrol. I drove it 120 miles round trip today and it felt the same with slightly less noticeable downshift changes when coming to a red light. Maybe a placebo affect.

I'm keeping the Magnafine filter for sure. Have used them in past Honda and Toyotas with 200,000+ mi. The OEM has a bypass valve if it becomes clogged just like the Magnafine but at twice the capacity and the built in magnet, this can only help. Here's a pic of the old OEM next to the new filter.

 

So now that we have had full disclosure, what you really needed was a normal drain & fill. You want to smooth things out? Muzzle the VCM. Makes a world of difference.
Part of the jerk is the shifts coinciding with the VCM kicking in or out. Honda/Acura cannot disable VCM as a fix. Here's the current favorite:

https://www.vcmtuner.com/products/vc...e-vcm-eco-mode

Although there are much cheaper ones without the features that one has.

 

I actually installed this within 2 weeks of ownership. Keeps the coolant output reading around 160 F. Love it

 

Congrats on the fluid change out. I'm liking the way that you did the drain and fill. You didn't put pressure on the system, you let the system pump the fluid out to a point and then refilled as you went along. I have performed drains like this for over 20 years on different cars I have owned and each time the transmissions felt great afterwards. I did mine the same way back a couple of months ago , but used Valvoline Max Life Syn fluid. Coming up when the weather gets warmer again I will install a trans cooler up front of the rad, to help keep the fluid in better shape for a longer duration of fluid life.
There was a post on resetting trans computer shifting system that I'm liking also. Turn the car to the on position cut radio and heating system off , don't crank car just turn on, then hold the gas pedal down for 30 seconds then release peddle and turn car off. Then crank and drive,,seemed to help mine,,good luck with yours.

 

I went over everything above and noticed something missed. You stated that the fluid coming out was red and hard to tell the difference between the old fluid and the new fluid. The original Honda DW1 is clear or a bit golden , in color. If your was red,that would mean the dealership put another brand fluid in the trans. My dealership replaced my fluid at 30 k miles and used Valvolean Maxlife syn fluid,,maybe yours did as well. On your question about the draining of the fluid and tq convertor ,,yes , the way that you made the drain, removed all of the old fluid from the convertor .

 

I dunno...I recently changed mine for the first time and the the new stuff was red, definitely not clear or golden. So was the old stuff (altho a bit darker). It's never been to a dealer so I'm pretty sure the old stuff was the original fluid.

 

Then maybe I was wrong about the OEM fluid,,thought it was an amber color. When I flushed out the system back a month or so ago mine was red because the dealership had filled with Maxlife Corrected about that now.

 

Poolman, thanks for answering my initial question that was still lingering. I feel better that I removed most of the older fluid. From here, I will do drain and fills with Castrol Full Synthetic every 20K miles. May be overkill but it's so easy to do and very cheap. As for the color, yes, OEM DW-1 is red. I did notice that Honda CVT HCF-2 that was in my CRV was light golden color.

 

You seem like you know what you’re talking about—I need advice! I’m looking at a 2018 (FWD) RDX, 147k miles. Trans fluid was changed at 30,633, 60,443, 89,267… and then CarFax shows a trans fluid change and flush at 129,995. Do you think they ruined the car with the flush? Was the flush to mask Transmission problems? Just wish I knew why they did a flush. Should I be concerned?

if you want to see the CarFax I’d love your opinion. Not sure if I can put a link in a post, but if you go to the Subaru Bachman website in Louisville Ky, and search used, it’s an Acura 2018 RDX with technology package.

 

The owner's manual states that a flush is required every 40,000 miles, but the owner played it safe and performed it more frequently.

 

The drain & fill interval for this transmission in other Hondas is 30k setting a code 3 every 4th time the oil life reaches 15% I think this Acura sets a code 3 every 6th. The maintenance minder is based on 7500 mile oil changes this engine used to have.
I'm not sure what to think about a CARFAX showing a flush. Kind of depends on who did it. The term flush gets used about automatic transmissions all the time.
Even the Honda service bulletin I linked calls the 3x fluid change a "flush". When I finally got an Acura dealer to perform the software update (highly recommended)
along with a single drain & fill at around 100k, it did some weird shifting. I bought a case of fluid from a dealer and had my own shop do another drain & fill within a week or two of the first. That stopped whatever was happening. (Reminds me another might be prudent) The software was developed to address premature breaking down of the fluid. It makes the trans hold gears longer. This includes not abruptly downshifting when you take your foot off the gas, the best part for me.
These transmissions can have failing shift solenoids need replacing as they age.

If anything, the consistent fluid changes would make me feel better about the service habits of the previous owner.

 

Thank you for this! An Acura tech from a Reddit thread helped me look the car up and he said this about the 130K “flush”:“Luckily the dealer that did the work reports to Acura's internal history program so I could actually pull it up and see what parts were billed. On that visit only 4 quarts of ATF were billed out, for a flush we do 3 drain and fills of about 3.3 quarts each so there should be at least 10 quarts of ATF billed out. So I don't think a flush was actually done and I think this was an issue between that dealer's service writing program and carfax.“
So sounds like a flush was never given.

Do you recommend the transmission software update, even though it caused shifting issues for you afterward? I wonder if the dealership will be able to tell if it’s had the most recent update. Like if they say “it was updated in 2023”, how will I know if that’s the most recent one—will dealership be honest about that? You said you had to convince your dealership to do it so I’m wondering if they get weird about it or something.

 

There was only one software update that I know of. I don't think the weird downshift I felt after the software was related necessarily, especially since another drain & fill made it never happen again. I also have an Odyssey with the same transmission and had the software done soon after I bought it used with 24K on it. The only reason it never got done to the RDX was a chicken shit dealer who I could never get to address anything on a Certified Pre-owned vehicle I bought from them. The whole purchase and service experience was misogynistic. The RDX was for my wife, she paid for it, they put my name first on the title, treated her like the little women when she would go in for services, an no one at Acura's online connection service we paid for would let her do anything because my name was first. (The TV in the waiting room played Fox News...)

Anyway, whenever I would drive the RDX I would find it irritating that it would abruptly downshift when taking your foot off the gas. I knew how nice the trans could be from my experience with my other Honda. I actually found out, from my Honda service manager (who has an Acura) that the management at the local Acura dealer had changed. ( I was trying to get my Honda dealer to do the software) I emailed the new service manager asking for the software along with a single drain & fill. I had to pay as the RDX was well out of warranty. He agreed to do it but even then cautioned that, once the software was updated I could not go back.*I assured him that it was all good. You have to pay for real tech time, service at dealers is often done by fluid change folks, not a full factory trained tech that is necessary to update software.
The irony? After this was done my wife says how nice it is not to have that judder anymore. The vary symptom the software addresses that she never mentioned...

I would see if the tech on Reddit can also check the database to see if the software was already done on this VIN.

*Honda has, in the past, done software updates without telling customers. This got them in deep shit, getting sued and such. It makes dealers nervous about doing them.