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Changing Automatic Transmission Fluid (is easy)

1M views 455 replies 133 participants last post by  Escher 
#1 ·
Changing the Automatic Transmission Fluid (ATF) in the Subaru Outback 4EAT is no harder than changing the standard engine oil. No joke.

Items required:

AT Filter (I got mine at the dealer. While you are there pick up some of the drain plug washers if you do not already have some from changing the oil.)

A socket wrench with a 17mm head.

A drain pan to catch the oil.

The Transmission Fluid. Five quarts should be enough. I use Mobil 1 ATF and can't say if its worth it or not. The transmission uses Dexron III/Mercon fluid. Available at any auto parts store, or even Walmart. Or right here on Amazon: https://amzn.to/2lfFtZp



Step 1: Toss a pan under the transmission pan. It is located about a foot behind your engine oil pan. If you cant change your own oil you might want to leave this to someone else.

Step 2: Unscrew the 17mm bolt on the drain of the transmission pan.
 

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#292 ·
Big thanks to Brucey and everyone else in the thread who posted advice. I changed mine over the weekend. I noticed a few things.

- Taking the driver's side jack stand out when you're draining will get a LOT more ATF out.

- Doing the above and removing the filter allowed me to drain 6 quarts on the nose. Actually a bit more because I spilled a little bit.

- Took every bit of strength I had and a breaker bar to get the drain plug out. I couldn't find a torque spec so I went with 20 ft-lbs because that's what I do on my VW oil drain plug. It hasn't leaked since.

- It's very difficult to get a good reading from the dip stick. It's not clear cut like the oil dip stick. Every time I checked it beforehand, I thought it was a little high. I only put in 5 quarts to start when I refilled. I took it for a test drive and measured when I got back. On the low end of normal, so I added a half quart. Looks as good as I can tell so I'm running with that.

- Went with Mobil 1 synthetic ATF. Shifts noticeably better. Used the VISA coupon code on Advance Auto Parts and got a significant discount. Ordered online and picked up in the store. Just wish that code worked for motor oil too...

- I always appreciate photos. Here are a few from my change:

Had a spill, as per usual. That's what the dropcloth is for. As you can see, fluid looks old and ready to be changed.


Draining in progress, after it stopped draining, and before I took down the driver's side jack stand.




After taking a jack stand out and removing the filter.


One last action shot.


I included the box of the filter as a reference for the part number if anyone needed it. We have a 2002 Subaru 2.5L automatic. Bought it online. Expensive shipping but saved a trip to the dealership and it was the same price as buying it in person.

I encourage everyone to do it. Very nice bit of maintenance. I noticed a difference, and as you can see, the fluid was ready to be changed. For reference, we have 80,000 miles on it.

Now on to front and rear differential fluid!
 
#293 ·
SubaruMN

Thanks for the report and great pictures.

Question: Was that the first time the AT filter was removed/changed and, if so, was there any difficulty in getting it off? I've read reports of the factory filter being "stuck on", like the drain plugs etc, and needing some innovative measures to remove.
 
#295 ·
This was the first time I removed the AT filter. It wasn't terribly difficult to get off. I have one of the metal band filter wrenches that gets tighter the harder you push. I had to push VERY hard and it came off right as I started thinking "oh no, this isn't going to come off..." I was really glad I didn't have to drive a screwdriver through it or any of the other creative measures people use.

The drain plug also was seized up pretty badly. It came off only with all of my might (which, honestly, probably only average "might") and with a hefty breaker bar. I didn't get nervous that it wouldn't come off. I replaced the washer on it so hopefully it will come off easier next time.

My 03 has the factory filter still on it. It's rusted/seized to the point I'm worried about destroying it to remove it. Figure fresh fluid is better than nothing.
I'm sure fresh fluid is better than nothing. One of the members here or at Bobistheoilguy.com (can't remember which) said he changed the filter at 100,000 miles and cut it open, and it looked brand new. Who knows for sure. I just decided to change it because it was only $20, a transmission is several thousand, and I was down there anyway. Also, mine was rusted on pretty badly (it's been in snow and salt country for several years) and it came off without much swearing.
 
#294 ·
My 03 has the factory filter still on it. It's rusted/seized to the point I'm worried about destroying it to remove it. Figure fresh fluid is better than nothing.
 
#296 ·
Just did this on my 04 Bean with 110K on the clock. I've drained and filled twice so far, might do a third time yet. It did tend to drain/take around 4 quarts each time.

One thing I noticed different is I've got dual exhaust back a ways in mine (apparently the H4 doesn't), and I ended up splashing a bit on it when I took the drain plug out.

My old fluid looked brown in color (as pictured).

Other thing is apparently I don't have a filter (pictured--you can see where my first spill went too!). It looks like if I did it wouldn't be fun to get to with the exhaust in the way. FWIW, Advance Auto had one for ~$15 that I bought, but I guess it's gong back now.

I went with Valvoline MaxLife fluid...and I used two funnels, one very similar to Brucey's (but I splashed some with that), so I added another on top of it, and didn't spill a drop after that.

In the short ride I went for, I think it definitely shifts smoother. I don't even feel it shift anymore. I put a video up to show, the beginning is normal acceleration up a hill, then I let off at the top and let it coast for a few seconds...it went into 4th immediately, which is nice...usually it will hang in 3rd for a while under the same situation. Punched it for a few seconds toward the end just to see if it geared down any quicker and how harsh the shift was under full acceleration, too. I think there's also an improvement there. Might as well make all you H4 guys jealous :D Gotta hear that Boxer roar once in a while. 2004 Outback LL Bean H6 After Transmission Fluid Change - YouTube
 

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#297 ·
Good report. That ATF does look quite "brown".

I believe the external ATF spin-on filter in the H6 is located in the left front fender, to the left of the battery. (Follow the ATF cooler lines forward toward the radiator. The filter is in the cooler line.) It's an awkward spot and does require the battery to be removed.

In any event, perhaps just as well. I nmy opinion, if the filter is changed, the Genuine Subaru AT filter should be used -- it's quite different inside compared to a standard engine oil filter, and as far as I know, no aftermarket filter manufacturer makes one. like this. (Most just list an engine oil filter that fits.)
 
#299 ·
Wow, I would have never guessed that's where it was. Maybe they put it there because the exhaust is in the way otherwise. The other one is already back at the store. I might order a genuine one and put it in place...if I remember to anyway. I'll probably also still drain and fill one more time. It's definitely an improvement so far, though.
 
#298 ·
The H6 filter is inside the driver fender, behind the splash guard. At least that's what's shown earlier in this thread.

And yikes! It needed that fluid change for sure. Did you try the tin foil trick to keep the oil off the exhaust?
 
#301 ·
That was the second drain, too, if I remember correctly. The first was even darker than that. Looked like old motor oil that hadn't been changed in 20K miles or something. The second time was lighter, and the fluid on the dipstick is cherry red now (wasn't after the first time). I will probably do one more drain and fill for good measure, though. I think it's safe to say that was the original fluid.

I didn't expect the oil to hit the exhaust when I took the drain plug out...it was just the first burst that hit it.

The rest was from trying just one funnel. The fluid splashed really bad when I tried to pour it in. Two funnels worked much better :D
 
#302 ·
I used this today while flushing my transmission, it helped a lot! Thank you! I didn't replace the filter, as it looked like it was seized on there and I didn't want to deal with a possible leak. It was an easy job!
 
#303 ·
Yeah I think the hardest part is getting an accurate level reading. I honestly have no idea whether mine is at a good level. I drained about 6 quarts (factory fill) and put in 5.5 because the dipstick was showing that it was quite high for both cold and hot readings. I've done everything including the warm up, park, put in all gears, place in park, check while idling, etc. It's a very difficult dipstick to get an accurate read on. I love the Subaru, but I've found all of their dipsticks poorly built to get good reads on. Why can't they just use the one with the hatch marks like my VW uses? I get a perfectly straight line with absolutely no oil above the line. No question.
 
#304 ·
Cleaning the ATF Cooler.

I would like to clean the rad attatched to the Auto box. I'm getting the feeling that there is some overheating somewhere. Can I disconnect the ruber hoses and suck out the fluid without doing any damage. I feel there may be a blockage somewhere. Can't find the filter on an 03 H6 anywhere.
Mike!
 
#305 ·
How much trans fluid lost thru open dipstick?

My daughter drives one of my 4 subarus. She has 2007 Impreza Sport. One week ago, she went to a quick oil change & now complains about a burning smell. I found that the trans dipstick was not fully seated last week after fluid was checked. Looks like fluid has flowed down, & one side of pan has fluid. My guess is that it blew onto the exhaust pipe to create burning smell. Dipstick does not show any fluid on it. Daughter drove about 450 miles since oil change-mostly highway driving. Any idea how much was lost? Any idea if permanent damage done? Could burning smell come from tranny itself? I am a weekend dabbler & rarely do much more than change oil and clean car (after my younger years experimenting on an old Chevy). Any opinions would be welcome.
 
#307 ·
My daughter drives one of my 4 subarus. She has 2007 Impreza Sport. One week ago, she went to a quick oil change & now complains about a burning smell. I found that the trans dipstick was not fully seated last week after fluid was checked. Looks like fluid has flowed down, & one side of pan has fluid. My guess is that it blew onto the exhaust pipe to create burning smell. Dipstick does not show any fluid on it. Daughter drove about 450 miles since oil change-mostly highway driving. Any idea how much was lost? Any idea if permanent damage done? Could burning smell come from tranny itself? I am a weekend dabbler & rarely do much more than change oil and clean car (after my younger years experimenting on an old Chevy). Any opinions would be welcome.
I agree with Plain OM's assessment. I would not drive it until you've topped it off. I really like Mobil 1 ATF. It's fully synthetic and much, much cheaper than the dealer stuff. Lots of people in this thread have used it too. I would get Amsoil ATF but since you're in a bind you need something you can swing by and pick up same day. I would actually recommend doing a drain and refill when you can. You have no idea what they put in there. First priority is getting it up to the right level though so it's drivable. A drain and refill is quite easy though.

I would take some photos and give the quick lube place a call and talk to the manager. This is unacceptable. They should pay for the dealer to do a flush, honestly. But that may not be an option.
 
#306 ·
My guess is that the quick lube started draining the transmission oil pan and realizing the error, closed it up, quickly (under-)estimated how much had come out, added ATF (perhaps spilling some as it has to be put in through the dipstick tube slowly) and then went on to find the engine oil drain.

I tend to doubt that ATF would blow out of the dipstick tube if the dipstick isn't fully seated, but that's another guess.

No way of telling what, if any, damage might have been done. Probably best to top up the ATF to the proper level, see how much it takes, and then see how it goes. (ATF should be at between the two HOT marks on the dipstick, with the engine and transmission fully warmed up, transmission in P (after moving through all gears) and the engine running. There's lost of info on this in this thread.)

The 2007 4-speed automatic uses Subaru ATF-Type HP, which is available from dealers.
 
#308 ·
Hey guys, sorry to invade on your forum, but i cant get any answers anywhere else. I have a LEGACY 2.5 Special Edition (with of course, the 4EAT). Im needing to change my tranny fluid and I couldn't find ANYTHING on my legacy forum because most everyone on there has GT's with 6MT's. Im assuming it would be exactly the same as this write up because its the same tranny? Anyone have any reason to believe otherwise?
 
#312 ·
It all matched up fine for my 07 Legacy special edition. I drained/refilled the pan, changed the filter, and then went ahead and flushed by pulling the cooling line. Measuring what you took out is imporant to get it close to the right level. It's annoying enough trying to guess the level from there!

(I only flushed it because I changed to Amsoil and didn't want a mixture of fluid. Not sure it was necessary, but I think some extra fluid is cheap insurance on a tranny.)
 
#309 ·
Should be the same.
 
#310 ·
...and if it isn't, take some pictures and I bet people here would still be willing to help you get through it. ;)

I've done this on a bunch of cars, and seriously, if it has a plug, it's essentially the same extremely simple process. Just like an oil change, just slightly more difficult to make sure the right amount of fluid gets put back in.
 
#315 ·
Questions:
I just did three drain and fills. Basically, drained once, filled once. Went out and drove a mile or two, getting through all gears (including reverse) a few times. Came back, repeated twice more. That's the proper method, right?

Also- when warmed up I'm now somewhere between the "cold" low and full mark, which is obviously no good. How many quarts would you guesstimate I need to go to the store and get to get to proper level?
 
#316 ·
when warmed up I'm now somewhere between the "cold" low and full mark, which is obviously no good. How many quarts would you guesstimate I need to go to the store and get to get to proper level?
The Full mark is when the ATF is at 60-80 degrees C. As there's no temperature indication (unless you have a scanner that indicates ATF temp), there's no easy way to know. However, when the outside temp is around 70 F, then driving for at least 10 miles would usually bring the ATF up to full temp -- longer when the outside temp is 30-40 F.

It doesn't take much to raise the level on the dipstick -- probably not more than one qt to go from the Cold marks to the Hot marks.
 
#317 ·
Hi all, have spent some good times reading through this thread. Firstly a question for those who drain through the cooler line.

Does the return line have any suction to it? Ie, could you put the return line in the fresh fluid and let it suck in what it pumps out, or is the fluid pushed through the cooler, and thus once disconnected, no suction in the return?

I'm mainly worried that air might enter the system through the return line as you carry out the process. Thanks for the help.

Also, is anyone in Australia using Nulons ATF, and what have the results been?
 
#321 ·
Anyone know how the fluid flows in the transmission? From what I can gather, the pump sucks it out of the sump and it goes to three places at once, torque converter, cooler, and galleries for control.

If so, I would think that using the cooler hose would be sucking new replaced fluid from the pan out, when what you want is the returning fluid from the TC, thus basically changing all fluid and not wasting any new fluid. Any thoughts?
 
#322 ·
over fill condition

recently bought a 1999 outback with the automatic transmission. After the first 100 miles the AT temp light started blinking. Not just 16 times but steadily blinking. I drove the car a few miles home and parked it. Next day, I start it up and everything was fine, no light blinking. I re seated the electrical connections to the tranny anyway and the car was fine for a couple weeks. I took it on another trip of about 200 miles and 100 miles out, I get the light and I can feel the torque bind issue. This time after sitting overnight, I drive about 30 miles and light starts blinking again. I returned home, let it sit overnight. Next day it is normal again. I start thinking about what is going on and the fact that I cant get an accurate reading on the dip stick. So I got to thinking that maybe the previous owner had over filled the tranny and when it got hot maybe the fluid was foaming and not building hydraulic pressure as it should. After lurking on this forum, I decided to drain the fluid and change the filter. I learned here that about 4 quarts should drain out. So I drain and get 5 and a half quarts. I put 4 and a quarter quarts back in. Still cant get an accurate read on the stick but the tranny now shifts better and no light after 150 miles, I believe I got it fixed. Anyone with similar experience?
 
#323 ·
Unfortunately my light is back flashing.I do know I have the correct amount of fluid in the tranny. I took the stock dipstick and painted it white so that I could correctly ascertain the level of the fluid.I am starting to think that it could be something electrical , possibly a bad ground. I see no performance issues, just the flashing light. Any ideas would be helpful
 
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