ATF Drain and Re-fill instructions, please comment!

[sdlmoab]

The awesome members of this forum helped me determine that I should preform an ATF drain and re-fill on my 94' Legacy wagon. I have experience doing basic maintenance work on cars but I have never done this procedure before. Therefore the main goal of this thread is to assemble, with the help of the members of this forum, a step by step set of instructions for preforming an ATF drain and re-fill on my vehicle. In addition if anyone has any advice or warnings, please comment!

Thanks
Sdlmoab

[Danny-G]

Get two of the gallon jugs of atf and a quart. With the car at operating temp, raise it and put it on jack stands, put a drain pan capable of holding eight quarts under the drain plug ( its on the left of the trans pan, towards the rear), break the drain plug loose and remove it. Be careful when taking the drain plug out, the atf can be over 350° F. After all the atf is out, put the plug back in, raise the car to remove the stands then put it back on the ground, with the car off add new fluid a little bit at a time through the trans dipstick tube (a funnel is a must), check the fluid level as you're adding it. Start the car and shift it into all gears from park to first and back to park. With the car idling, check the fluid and add as much as is needed to get to the lower level on the dipstick. Take it for a quick spin and enjoy.

That's from a Haynes manual (minus the last sentence) for first and second gen legacies. Its a pretty easy job actually, I've done it to both of my cars in the yard with hand tools.

[rallyak]

Also there are two dipsticks, one for the diff on the right side (passengers side) and one for the ATF left side (drivers side). I've seen a lot of people put ATF in the wrong spot and then have to change the diff oil also.

[wtdash]

To add to Danny-G's, the way I do it and has been recommended on other sites, is to repeat the process 3x total. This gets most of the old ATF out of the system. There's a lot of it left in the torque converter if you only do it once.

As stated, refilling is a little tricky. The main thing is to NOT put in too much. Assuming you're ATF fluid is full when you start, the amount you drain out should be replaced w/the same amount, then follow the directions above to make sure it's full.

There's a 'cold' and 'hot' level on the Trans dipstick, too.

I'd highly recommend getting an external trans cooler, too.
TD

[sdlmoab]

Thanks for the replies.
Here is what I have so far. Please comment with suggestions and advice!

1) Get the car up to operating temp.

2) (with the car off?) Open the ATF drain plug (I assume its a bolt, like the one for the engine oil), and let the ATF fluid flow out.

3) re-insert the ATF drain plug.

4) With a long funnel, add new AFT fluid to the ATF reservoir; add the same amount of fluid that was removed.

4) Start the car and shift it into all gears from park to first and back to park.

5) Drive car (how long?), repeat procedure (how many times?).

Also, is there a filter that needs to be replaced?

[wtdash]

Thanks for the replies.
Here is what I have so far. Please comment with suggestions and advice!

1) Get the car up to operating temp.

2) (with the car off? Yes, OFF) Open the ATF drain plug (there are 3 plugs - 1 for the Oil, the Differential and the ATF - make sure you're doing the correct one), and let the ATF fluid flow out.

3) re-insert the ATF drain plug.

4) With a long funnel, add new AFT fluid to the ATF reservoir (There is no reservoir - the dipstick is used to fill and check the fluid.); add the same amount of fluid that was removed.

5) Start the car and shift it into all gears from park to first and back to park.

6) Check the Fluid Level - fill a small amount (ounces - not pints/quarts) and check; repeat 'til @ the Hot - Full level. With the car idling in Park.

7) Drive car (5 miles/enough that car shifts thru all gears), repeat procedure (2 MORE times).

Also, is there a filter that needs to be replaced?Not on the older models. Some might have an inline filter ADDED that was installed directly below the washer fluid reservoir. This is between the trans cooler built-into the radiator and the trans.

[sdlmoab]

Thanks for the replies.
Here is what I have so far. Please comment with suggestions and advice!

1) Get the car up to operating temp.

2) (with the car off? Yes, OFF) Open the ATF drain plug (there are 3 plugs - 1 for the Oil, the Differential and the ATF - make sure you're doing the correct one), and let the ATF fluid flow out.

3) re-insert the ATF drain plug.

4) With a long funnel, add new AFT fluid to the ATF reservoir (There is no reservoir - the dipstick is used to fill and check the fluid.); add the same amount of fluid that was removed.

5) Start the car and shift it into all gears from park to first and back to park.

6) Check the Fluid Level - fill a small amount (ounces - not pints/quarts) and check; repeat 'til @ the Hot - Full level. With the car idling in Park.

7) Drive car (5 miles/enough that car shifts thru all gears), repeat procedure (2 MORE times).

Also, is there a filter that needs to be replaced?Not on the older models. Some might have an inline filter ADDED that was installed directly below the washer fluid reservoir. This is between the trans cooler built-into the radiator and the trans.

Once again thanks for your reply.
I still have a few quick questions.

Question 1) How much ATF fluid do I need to purchase to perform the drain and fill procedure 3 times.

Question 2) Should I buy a specific type or brand of ATF? (aside from the one the auto store recommends for my vehicle)

Question 3) Can I do the 3 separate drain and fill procedures a week apart, one per week for three weeks?

[wtdash]

Question 1) How much ATF fluid do I need to purchase to perform the drain and fill procedure 3 times.
Roughly 1/2 of the total capacity is in the pan. I 'think' (check the Owner's Manual) yours hold 9 Quarts. So buy 5 qts for the first go round and see how much it takes.

Question 2) Should I buy a specific type or brand of ATF? (aside from the one the auto store recommends for my vehicle)
What's your budget? You can buy the synthetic stuff, but it gets expen$ive. I'd just buy the least expensive 'name brand' fluid. It should use the Dexron II/III/Mercon per the Owner's Manual. You won't find a Dexron II - it's no longer made. But Dexron III should still be out there. I'm NOT an expert on fluids and not 100% sure the newest Dexron VI is backwards compatible for Subarus. You can always buy the ATF fluid direct from Subaru, if you want.



Question 3) Can I do the 3 separate drain and fill procedures a week apart, one per week for three weeks?

Yes.

GL,
Td

[Legacy777]

Here are some additional comment/clarifications.

The ATF drain plug is on the driver's side of the transmission pan.

Due to the age/mileage of these transmissions sometimes the anti-drain back valve coming from the torque converter leaks or doesn't hold. As a result more of the ATF drains from the transmission. You could end up with 4-5 quarts or more draining vs. 3-4 quarts. So keep an eye at how much drains out so you can refill with the approximate amount.

On the initial fill, you MUST use the "COLD" low and full marks to check the level, NOT the "HOT" low and full marks. Once you have the level between the "COLD" low and full marks, drive the car for 5-10 miles so the ATF gets up to normal operating temperature. Park on a level surface, turn all the accessories off, cycle through the gears, P to 1 and back to P, leave the engine running at idle, and then check the ATF level using the "HOT" low and full marks.

Regarding repeating the process multiple times, I'd wait and see how dirty the ATF looks and how much comes out. If the fluid looks pretty good and you get a lot out, I would not bother draining and refilling again.

Newer versions of Dextron ATF should be backwards compatible.

[sdlmoab]

GL,
Td

Is a filter change a necessary part of this procedure?
My Legacy has just about 100k miles on it, and as far as I know the filter was never changed.

[Legacy777]

There is only an internal screen and not a filter. It should not need to be cleaned.

The external add on filters are meant to work for the life of the car. You can replace it if you want, but I'd suggest just doing the drain and refill.

[sdlmoab]

Thank you everyone for all your awesome help!!