ATF flush adapter

yugrus

Contributor
:
CX-5 GT
There were discussions on the boards about inability to exchange all transmission fluid in SkyActiv transaxle. The problem is that there is no obvious way to hook up to the fluid flow, because Masda employs the liquid-to liquid ATF cooler with only coolant fittings accessible. Partial fluid exchange is very doable and easy through the dedicated drain plug, or the pan drop with filter replacement. However, this replaces about a third of the total amount of fluid in the transmission. The efficiency of the subsequent drain-and-fill procedures diminishes rather quickly, and the fluid is expensive.
Here's my approach to solving the problem. I really hope that the link to my shared album in Google Photos work, as I don't really want to go through resizing of the files.
I ordered a spare ATF cooler on Aliexpress. About $30. Without knowing what's inside, I hacked the top of it off. It revealed some sophisticated mesh of interchanged layers of thin aluminum fins, where coolant and ATF travel on top of each other without mixing, exchanging the heat.
I've got some standard hose fittings, measured their lenghth and hacked the cooler some more, so the fittings just cover and block all fluid access slits in the ATF ports. I pressed the fittings in with some Gasketmaker black silicone.
Now I have something with access to the ATF flow. One port will be inlet, another -outlet. I am going to drain the ATF from the pan and remove the ATF cooler from the transmission. It will then hang on the coolant lines throughout the procedure, not participating in anything.
I'll attach my adaprer to the transmission in place of the cooler, then I will attach hoses to fittings, submerge one in fresh ATF, another into the waste bucket. Fill the transmission through the dipstick hole. Then start the car watching the new fluid being sucked in, and old fluid expelled out by the transmission's pump. When it runs out of new fluid, turn the engine off. Replace the adapter with ATF cooler that is patiently hanging beside the mess, looking good, doing nothing. Done.

The procedure is more involving then in some other cars, but quite doable. I will post an update when I replace the fluid. It will take quite some time though...

https://photos.app.goo.gl/jJH3WKDcc2eYx4su9
 
Please DO report back.

Me thinks that partial flush done every 40K-50K is plenty.

If I went into so much trouble to perform this with your method (which still needs to be proven to work), I'd drop the pan, replace ATF and the FILTER, which should provide more benefits with comparable amount of work.
 
Please DO report back.

Me thinks that partial flush done every 40K-50K is plenty.

If I went into so much trouble to perform this with your method (which still needs to be proven to work), I'd drop the pan, replace ATF and the FILTER, which should provide more benefits with comparable amount of work.
Nothing prevents anyone from doing the above AND replacing ALL ATF at once. I don't see how's that way more work, given that you're already there. Again, partial flush replaces about third of the fluid, the rest keeps deteriorating. You're partially replacing fluid to kind of fix that, but the majority of the fluid there is still old after you're done.
The cooler is just three bolts away from being taken out...
Just a discussion to give a rationale for the potentially beneficial method.
 
Looks like a good adapter to attach an external oil cooler.
 
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Wonder if you could use that to attach an external oil cooler?
Not done this way, no.
I'm sure sooner or later some aftermarket supplier will come up with the version of the cooler with external ATF cooler fittings, they have made them for older Mazdas. Besides, the existing cooler has the design provision for the external fittings, they just didn't add them.
I don't see the point though. It's not that the car is a torque monster that can tow the yacht out of the water, and up the mountain... It's unibody SUV... The ATF temperature is dead stable on my Forscan, less or equal to the coolant temp, no mater what you do.
 
Nothing prevents anyone from doing the above AND replacing ALL ATF at once. I don't see how's that way more work, given that you're already there. Again, partial flush replaces about third of the fluid, the rest keeps deteriorating. You're partially replacing fluid to kind of fix that, but the majority of the fluid there is still old after you're done.
The cooler is just three bolts away from being taken out...
Just a discussion to give a rationale for the potentially beneficial method.

Hey, Yugrus, do you have a part number for the cooler you ordered? I've got a '16 and AliExpress doesn't list mine. Thx.
 
I don't, but there's only one SkyActiv transmission for all CX-5 years... If it looks like that, this is.
 
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