DIY 5EAT ATF Flush

Did the job today. Went through 11.5 quarts of fluid and now it's nice and red instead of brown. A messy job to be sure, especially as my funnel wouldn't fit all the way inside the stupidly small trans. dipstick/filler tube. I couldn't even fit my hose style funnel in it that fit easily inside the front diff dipstick/filler tube. Regardless though, even at only 46k miles the fluid looked to be in need of changing. I can not even believe Subaru says this service is optional! I don't know if I'll do this again in another 30k miles or another 50k miles. I think I'll go ahead and change out the filter next time too.

Do it again in 30k.

I bought funnels that fit from either Harbor Freight or Northern Tool. Not the most easy size to find, but a lot better than having it not go in, and making a mess.

Is the transmission cooling line part only applies to GT model?

Do I need to do this for non-Turbo model? Does it even exists for non-Turbo model?

Edit:

Answer to myself: All cars must have their ATF go trough the cooling system somehow. So, duh, yeah, non-GT model has cooling line.

^Wait. I just read this again and watch the video.

So, instead of draining the AT fluid from the bottom of the car by taking out the plug, we're actually draining using the line??

I also notice post #16, so, we can use both technique? Drain the pan, insert matching amount of liquid, then drain it again using the cooler line.

This is amazing. I've never thought of doing it this way. I wonder if this is possible at all to do this on the 2003+ Honda Accord. The DIY in the Accord forum never mentioned about draining via the cooler line.

Edit: I think this is exactly what Honda is cautioning us not to do. They're against the complete flush and only suggested 3x drain-and-fill.

I agree with draining the pan first--also ensures that you are pumping fresh fluid through the system from the get-go. There is a crush washer there, it's not copper but it is one-time-use and should be replaced.

BarManBean, did you mean, draining the pan first and then refilling the pan BEFORE you do the cooler line method? OR, draining the pan and then proceed with the cooler line method?

Edit: I saw another DIY drain-and-fill on another website and got a better idea on how it works. Plus, reading the PDF on Transmission Cooler clarified it even more.

Edit2: Not to put words on BarManBean's mouth, but, I think he would suggest to drain the pan and fill back with new fluid before moving forward with the cooler line return "flush" method.

_karu_, you're over-complicating and unnecessarily questioning a very simple thing.

A pan drain and fill only removes and replaces what's in the pan. This is not what we are talking about.

This 'DIY Flush' method pumps the old fluid from the pan, through the transmission system, and some of that fluid goes through the cooler line loop. The pan is still getting drained, but through the system and out the cooler hose. So there is ZERO point in touching the pan drain plug, unless you really like to do extra steps that add no value, such as crawling under the car when you do not need to. The ONLY point of fluid output can be the cooling loop, which will get out almost all old ATF after a few cycles of emptying and filling.

Now I know how rao feels, people can't leave 'well enough' alone.

Thanks, ClimberD@HexMods!

Having read trough the thread carefully several times, it dawned on me how I over complicated the whole thing. I normally only do drain-and-fill (1x) on my previous car, so, this flush method freaked me out a bit initially. Mind you, I'm not a car expert, just regular DIY-er following instructions in the forums.

BTW, you mentioned that the point of NOT doing draining the pan is for us to skip the crawling part. Are you suggesting that I could unplug the cooler line return hose directly from under the hood, without crawling down? This didn't hit me because all the pics and videos are showing the line from underneath the car.

I will trace the line and post the pic of it later. Mind you, as of today, I've only owned the Legacy for less than 1 week. I beg your pardon if I sound too needy or asking too much details.

You may still have to get on your back under the car to easily get to the line, unless you can reach it from above (maybe you can, you can certainly see many cooler lines from above).

Big difference between reaching 6" under the car for a cooler line, vs reaching all the way to the middle of the underbody.

You certainly can, and its fine to do so, but I still stand my ground, because the first few quarts from the pan will be mixed with the rest of the system's old fluid, and should be disregarded in the flush process regardless. Also note the drain plug does a bad job of removing all fluid from the pan (which is why after draining the pan you can still get splashed with old ATF when then removing the pan), and the VB fluid pickup sits low in the pan (similar depth).

No matter how you do it, the indicator to stop the cycling is when the fluid coming out of the cooler line is the same as what you put in, meaning that regardless of whatever point the mixing happened (just in system, or in pan and in system), the mixed fluid should also be expelled, since you're already there.

One of those things where the theory is superior, yes, but the reality says it just does not matter, so why bother unless you're already under there draining the oil anyways, and if to the operator it's more about the journey than the destination, which is fine.

Hm...

Knowing how far in the middle the drain plug is, I'm really leaning towards ClimberD@HexMods' method of just draining via the cooler line. However, the OCD-ness inside of me is telling me to do what BarManBean's suggested, which is to drain the pan beforehand.

Hmmm...decision decision.

The thing is, unlike the Accord, the car sits lower and I can't reach the drain plug without using jack stand. With the Accord, I can just slide in and unplug the drain plug without even using a jack.

Is this the same process as what would be required for the 4EAT? I wanna do the GF's fluids(HA) but want to verify this before I go drop the cash. Can I use Mobil ATF or should I go Subaru fluid on the 4EAT

Should be a very similar process on this and almost any AT car, just lines being in a different place.

About the fluid, I do not know what the right fluid is for the 4eat. Definitely research that more thoroughly before you go with something other than oem. The universal fluids, aren't. For example, I find Amsoil ATF to NOT work well in many of the applications for which it says it is fine. However, damn does it work well in the 5eat.

thanks for this well explained DIY, got all the parts for extension tubing and gonna give it a whirl this week. really excited to be able to solve the hard shift that i'm experiencing between 2nd/3rd, and i'm at 80k. subaru OEM was about $6/quart, not that bad compared to the stealership doing the work. plus i learned something!

If this doesn't work, then at least your trans will have some good fluid to use to actuate everything, which is better grounds for a TCU reset. First do the DIY ATF Flush though, then TCU reset if needed. Let us know how you make out.

worked perfectly, only snafu is that i drained 2qt too much out, and need to pickup some more of the subaru OEM stuff from the dealer. i noticed a small leak, got worried and then realized it was drips from my funnel, nothing from the pan or anywhere else (just gravity and a dripy hose)

thanks again! i also got a great funnel from advanced, with a cap on the end. Nice and clean!

EDIT: TCU reset, i guess i can do that with a reflash using my Accessport? never heard it called a TCU, thought it was the ECU. but i get your drift.

worked perfectly, only snafu is that i drained 2qt too much out, and need to pickup some more of the subaru OEM stuff from the dealer. i noticed a small leak, got worried and then realized it was drips from my funnel, nothing from the pan or anywhere else (just gravity and a dripy hose)

 

thanks again! i also got a great funnel from advanced, with a cap on the end. Nice and clean!

 

EDIT: TCU reset, i guess i can do that with a reflash using my Accessport? never heard it called a TCU, thought it was the ECU. but i get your drift.

I don't think the Accessport does TCU resets. It only interfaces with the ECU, unless something changed recently, which isn't likely coming from Cobb.

sorry to bump an old-ish thread.

I'm at about 65K miles right now. fluid still looks to be a nice red though.

This is my first auto trans car.

Still probably going to pick up some royal purple ATF and do this. I was going to take it somewhere eventually and have a shop do it, no need to now. lol

might as well do the Diffs at the same time, not going to hurt anything other than a small dent in the wallet. haha

better than the giant dent from replacing car parts though.

I had done this very successfully on my 05 XT a few years ago. I repeated this recently on my 08 tribeca (same 5EAT). I had a messy surprise. The line that comes off the bottom of the transmission cooler is NOT the return line. It's the supply. This is different than my XT. Had the bucket all set up for it to come out of the bottom, but it came from the other side of the line and made quite the mess! I also tried the predrain and fill to see if I got clear fluid out sooner. However, that didn't seem to save anything, I could have easily just done it the original way of never opening the drain plug. Used 10 qts and it was clean at the end. Guestimated the spills and was about a 1/2 qt low (this is what I determined was the difference between full and low lines - interested if others found the same).

Still, nice to know I got the Brakes Plus junk out of there the previous owner put in based on their recommendation. No idea what the fluid actual was, but it smelled and looked like gear oil!

I had done this very successfully on my 05 XT a few years ago. I repeated this recently on my 08 tribeca (same 5EAT). I had a messy surprise. The line that comes off the bottom of the transmission cooler is NOT the return line. It's the supply. This is different than my XT. Had the bucket all set up for it to come out of the bottom, but it came from the other side of the line and made quite the mess! I also tried the predrain and fill to see if I got clear fluid out sooner. However, that didn't seem to save anything, I could have easily just done it the original way of never opening the drain plug. Used 10 qts and it was clean at the end. Guestimated the spills and was about a 1/2 qt low (this is what I determined was the difference between full and low lines - interested if others found the same).

 

Still, nice to know I got the Brakes Plus junk out of there the previous owner put in based on their recommendation. No idea what the fluid actual was, but it smelled and looked like gear oil!

That is good to know! Will add a note about your Tribeca experience. I have often wondered what one-size-fits-most fluids these discount chains are using. If it's black, then it shouldn't be in the 5EAT.