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Discussion Starter #1
Most seem to think mulitiple sequential changes is best way to swap out most of the ATF an automatic transmission. At todays ATF prices $4-$8, this is an expensive procedure. I replaced all my ATF yesterday (10 qts) and it's not difficult. W/i capacity of an DiY'r. Following are steps I used.

1) Elevate car on ramps for access to drain the ATF. To keep car level I jacked rear up to level w/ hydraulic jack to allow complete draining of trans pan. You could also lower the car back down after step 2)

2) Replace drain plug and refill trans volume ~2.5 qts w/ new ATF.

3) Disconnect transmission cooler supply line at the radiator. It's the short line connecting to the driver's side connection radiator.

4) Install a short (2-ft) length of clear plastic tube ( ~ 5/8" ID tube) over the released rubber hose trans cooler line to extend the line into a catch pan. You may need to make a measurement of tube dimensions and go to a hardware store to get a piece of clear plastic tube. I had a piece in scrap that fit w/ some effort to push the large tube over the smaller. No clamp is needed.

5) Direct the drain extension into a catch pan. A clear or translucent (1 gallon jug) makes a good catch pan. You want to be able to easily see the quantity of the fluid entering the catch pan.

6) Start engine and run 1-2 qts into catch pan. IMPORTANT! This only takes 10-15 secs! I found I had just enough time to start engine, step to front of car and inspect fluid/quantity, and return to cut engine off. Of course a helper would make this step much easier, but it is possible to do solo as I did yesterday when my helper (wife) was out of town. This step requires clear access between keyswitch and your catch pan to allow you to access and stop the engine quickly.

7) Replace drained fluid amount w/ new ATF. I simply guessed approx. fluid amount. If you have a graduated catch pan, it would allow more precise volume replacement.

8) Repeat 4-5 times depending how much fluid you drain. The total trans (torque converter plus trans pan) volume is ~10 qts, so you must replace ~ 7.5 qts w/ this sequential drain procedure.

I found the fluid began to clear on my last drain before final top-off w/ ATF. The fluid still had a small amount of old fluid contamination but was very clear and red. You could "over-flush" to provide additional removal of contaminated fluid. You could also replace the ATF filter to reduce contamination of new fluid.

Regards
 

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1999 Forester L
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46 Posts
TexFoz -
A big mahalo for sharing your tip. I followed your instructions, after checking out some other threads on the same idea, and did it today.

2 things surprised me.
1. The ATF filter is a life of transmission part? I replaced it anyway at a cost of $28. wow.

2. It took longer than I thought it would to get the right level of ATF without overfilling. Lots of 1/2 quart additions along with starting and running through ALL gears, then checking the level.

Now it cruises, shifts buttery-smooth and I know it's good for several more thousand miles.

Aloha!
 

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Premium Member
2019 Crosstrek 2018 XT
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14,167 Posts
Certainly nothing wrong with going this route. I still prefer the 12,000 mile drain and fill. Replaced the filter at 50K miles. I don't ever expect a tranny problem.
 

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1999 L 4AT
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1,183 Posts
TexFoz -
A big mahalo for sharing your tip. I followed your instructions, after checking out some other threads on the same idea, and did it today.

2 things surprised me.
1. The ATF filter is a life of transmission part? I replaced it anyway at a cost of $28. wow.

2. It took longer than I thought it would to get the right level of ATF without overfilling. Lots of 1/2 quart additions along with starting and running through ALL gears, then checking the level.

Now it cruises, shifts buttery-smooth and I know it's good for several more thousand miles.

Aloha!
It's good to hear you got things sorted out! :biggrin:
 

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2005 Forester XT 4EAT
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173 Posts
I do this to most of my cars, but I disconnect the return line to the transmission that way I flush out the cooler.
 

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2009 5MT manual
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85 Posts
Does anyone have a pic of where to disconnect at the transmission cooler line ... I'd like to try this on the wife's 2005 but am unfamiliar with the cooler plumbing (I just did the simple pan drain on my 2000) ...

And this may be a dumb question, but why don't folks run the transmission briefly after draining the pan (to get more of the old fluid out) ... I must assume the tranny would not like this?
 

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The Modfather
2019 Impreza 5dr Sport - Manual
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8,052 Posts
Do you mind if I cut and past this somewhere on scoobymods, looks like a good procedure to me.
 

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Discussion Starter #8
Does anyone have a pic of where to disconnect at the transmission cooler line ... I'd like to try this on the wife's 2005 but am unfamiliar with the cooler plumbing (I just did the simple pan drain on my 2000) ...

And this may be a dumb question, but why don't folks run the transmission briefly after draining the pan (to get more of the old fluid out) ... I must assume the tranny would not like this?
There's only two connections. The drivers side is feed from trans to radiator and pax side is return from radiator to trans. As someone suggested, if you disconnect return you would also flush the trans cooler. Also gently blow on return line to trans to push trapped fluid in the hose/tubing back into reservoir.

good luck
 

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2009 5MT manual
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85 Posts
OK. I was thinking of trying this on my 2000 but the hose fittings look like they might not loosen or re-tighten easily (if at all) but should be ok on the 2005 ... thanks again.
 
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