Technical aspects of automobiles

DIY Automatic Transmission Flush

OK I finally decided to give something back to the net.  I decided a
few weeks ago to flush the transmissions on 2 cars.  2000 Toyota
Avalon with 70K and 1997 Toyota Corolla with 120K.  This was brought
about by 2 things.

I tried to get the Corolla flushed at a local quick lube and they
asked if it had ever been flushed before.  It is my wife’s car and she
had it before we met so I didn’t know.  When I told them, they said
they wouldn’t flush it because it might mess up the transmission and
they didn’t need the grief.

2nd reason was I had changed the AT filter on the Avalon about 3 years
ago and it has leaked ever since.

Let me start with this.  If you transmission isn’t leaking DO NOT
replace the filter.  It isn’t worth it.  It is a real mess.  If you
insist on doing it I’ll describe it later.   JUST DON’T DO IT is my
advice.

When I said I had replaced the filter before I knew what a mess it was
going to be but  I had created a leak that was getting worse.  I
torqued the pan bolts to spec in the recommended order but it leaked.
I tightened the bolts but it didn’t help.

1st a little background.  Your automatic transmission has a pickup
that takes fluid from the pan and draws it through a screen that acts
like a filter.  Then it goes to the torque converter is used in the
fluid portion of the transmission.  In this process it gets hot and
needs to be cooled.  So it comes out of the top of the transmission
and gos to the radiator.  After cooling it returns to the bottom of
the transmission pan.

We are going to disconnect the return line and let the transmission
pump old fluid into a jug while we pour new fluid in the top.

Step 1) Get a clear/transparent 1gal jug.  Milk jug or windshield
washer work great.

Step 2) Mark 1Qt lines on the jug.  I used a large measuring cup.  I
measured out a quart of water then poured it into jug and marked
side.  Repeat 4 times.

3) Find the tubing that connects the radiator to the AT pan.  Get an
idea of the size and go to home depot or lowes and buy some soft
tubing that is about the same size.  I bought 2 different sizes just
to be sure.

4) Drain AT pan.  My cars both have a drain plug but I’ve read that
not everyone is so lucky.  If yours dosen’t have a plug I’ll give some
suggestions later.  When you drain the pan meausre how much you just
took out using the jug you just marked.  Mine took 4 qts but the full
system is 8 qts.  The rest is in the torque converter and in the
radiator.

5) Put in new fluid to replace what you just took out  + 1/2 to 1
quart additional.  You have to fill AT fluid through the hole at the
AT dip stick goes in.  The reason for the extra is you don’t want your
transmission to ever be dry.

6) Find the hose that comes from the radiator and goes to the bottom
of the AT pan.  This will be the return.  If you disconnect it at the
radiator just take the hose you bought and put it over the outlet.
Make sure to have a drain pan to catch anything that drips.

7) Now you are ready to start.  Open as many qts of AT fluid you think
you will need.  In my case I added 8 quarts total so I opened up3 qts
and had them ready.  Remember I put in 1 extra when I refilled.  Put a
funnel in the fill hole and get everything ready to pour.

8) You’ll need a friend for this.  One of you will start the car and
work it through the gears while your foot is on the break.  This
should open up all the valves in the transmission.  When the engine
starts running fluid will start to fill up the hose you connected.
Put put the end of the hose in the marked jug.  As you see fluid start
to fill the jug start pouring the new fluid in.  As it crosses the 1qt
line you should have added your 1st qt. Do this until the fluid runs
clean or you put in as much as you want.  I only put in 8 quarts total
because I bought synthetic for the Avalon and it cost $10 per qt.  For
the corolla I bought 2 gallons and poured them both through.

9) Make sure you put in as much total as you drained out.  Then
reconnect the hose and clean up.  You just performed a $90 service for
$20 -$30.  If you can change your own oil you can do the flush is was
pretty easy.

If you don’t have  a drain plug. You have 2 choices.  1)  Follow the
instructions above just don’t drain pan.  You’ll be mixing new fluid
with the old fluid in the pan so it may take more fluid to run clean
but anything is better than nothing.  2) Suck out the fluid through
the fill hole.  There are some systems out there for this.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=45403

Finally if you insist on dropping the pan I have 1 phrase that will
save you a lot of time.  "Permatex The right stuff for imports"  This
stuff is great.  I came across it in another post.  Here is what I
did.  Remove the old gasket.  I used scotch bright to clean up both
surfaces.  Then I put a thin bead of this stuff all around the pan.
Make sure to go around all the bolt holes.  Then put the pan on with
this stuff still stickey.  Tighten the bolts to finger tight with
wrench.  So just snug them no real torque.  Wait a day.  Then torque
bolts to spec.  I did this and have no leaks.

Good luck.  My next project is to replace the AC compressor on my
mothers Honda.  I’ll post what I find if it works.

.
posted by admin in Без рубрики and have Comments (3)

3 Responses to “DIY Automatic Transmission Flush”

  1. admin says:

    After learning this lesson on a Mercury Topaz (and getting a nice ATF
    shower in the process), I am using the cheaper Harbor Freight siphon
    pump to pump the ATF out the dipstick tube on an ’87 Blazer. If you
    park it facing downhill, or jack up the back, you can get more fluid
    out of the pan as it sloshes forwards.

    One day I’d like to sit down with every automotive engineer that ever
    designed an AT without a drain plug and slap them all silly.

  2. admin says:

    nice writeup!  i’m planning to perform such flush on my sterling 827
    with acura legend engine and transmission.

    Anyway could you write more details about that person in the car,  how
    exactly to go through all the gears?

    mine gears are:
    P–R–N–D–S–2

    back and forth?   what time intervals?  like  P—2seconds—-
    R—–2seconds—-N-……….

    i have an idea to additionally lift the front of the car, so the front
    wheels would be up in the air, and then go through all the gears, and
    finally set it to D,  and press the gas pedal, so it would go through
    all the gears, but maybe its completely unnecessary  and doesnt do
    much?     what do you think?

    i’m also planning to install little oil cooler in front of the
    radiator,  although i dont do any towing, but read its highly
    recommended and very good for the tranny.

  3. admin says:

    On Oct 22, 5:14 pm, ctur…@austin.rr.com wrote:

    - Hide quoted text — Show quoted text -

    > OK I finally decided to give something back to the net.  I decided a
    > few weeks ago to flush the transmissions on 2 cars.  2000 Toyota
    > Avalon with 70K and 1997 Toyota Corolla with 120K.  This was brought
    > about by 2 things.

    > I tried to get the Corolla flushed at a local quick lube and they
    > asked if it had ever been flushed before.  It is my wife’s car and she
    > had it before we met so I didn’t know.  When I told them, they said
    > they wouldn’t flush it because it might mess up the transmission and
    > they didn’t need the grief.

    > 2nd reason was I had changed the AT filter on the Avalon about 3 years
    > ago and it has leaked ever since.

    > Let me start with this.  If you transmission isn’t leaking DO NOT
    > replace the filter.  It isn’t worth it.  It is a real mess.  If you
    > insist on doing it I’ll describe it later.   JUST DON’T DO IT is my
    > advice.

    > When I said I had replaced the filter before I knew what a mess it was
    > going to be but  I had created a leak that was getting worse.  I
    > torqued the pan bolts to spec in the recommended order but it leaked.
    > I tightened the bolts but it didn’t help.

    > 1st a little background.  Your automatic transmission has a pickup
    > that takes fluid from the pan and draws it through a screen that acts
    > like a filter.  Then it goes to the torque converter is used in the
    > fluid portion of the transmission.  In this process it gets hot and
    > needs to be cooled.  So it comes out of the top of the transmission
    > and gos to the radiator.  After cooling it returns to the bottom of
    > the transmission pan.

    > We are going to disconnect the return line and let the transmission
    > pump old fluid into a jug while we pour new fluid in the top.

    > Step 1) Get a clear/transparent 1gal jug.  Milk jug or windshield
    > washer work great.

    > Step 2) Mark 1Qt lines on the jug.  I used a large measuring cup.  I
    > measured out a quart of water then poured it into jug and marked
    > side.  Repeat 4 times.

    > 3) Find the tubing that connects the radiator to the AT pan.  Get an
    > idea of the size and go to home depot or lowes and buy some soft
    > tubing that is about the same size.  I bought 2 different sizes just
    > to be sure.

    > 4) Drain AT pan.  My cars both have a drain plug but I’ve read that
    > not everyone is so lucky.  If yours dosen’t have a plug I’ll give some
    > suggestions later.  When you drain the pan meausre how much you just
    > took out using the jug you just marked.  Mine took 4 qts but the full
    > system is 8 qts.  The rest is in the torque converter and in the
    > radiator.

    > 5) Put in new fluid to replace what you just took out  + 1/2 to 1
    > quart additional.  You have to fill AT fluid through the hole at the
    > AT dip stick goes in.  The reason for the extra is you don’t want your
    > transmission to ever be dry.

    > 6) Find the hose that comes from the radiator and goes to the bottom
    > of the AT pan.  This will be the return.  If you disconnect it at the
    > radiator just take the hose you bought and put it over the outlet.
    > Make sure to have a drain pan to catch anything that drips.

    > 7) Now you are ready to start.  Open as many qts of AT fluid you think
    > you will need.  In my case I added 8 quarts total so I opened up3 qts
    > and had them ready.  Remember I put in 1 extra when I refilled.  Put a
    > funnel in the fill hole and get everything ready to pour.

    > 8) You’ll need a friend for this.  One of you will start the car and
    > work it through the gears while your foot is on the break.  This
    > should open up all the valves in the transmission.  When the engine
    > starts running fluid will start to fill up the hose you connected.
    > Put put the end of the hose in the marked jug.  As you see fluid start
    > to fill the jug start pouring the new fluid in.  As it crosses the 1qt
    > line you should have added your 1st qt. Do this until the fluid runs
    > clean or you put in as much as you want.  I only put in 8 quarts total
    > because I bought synthetic for the Avalon and it cost $10 per qt.  For
    > the corolla I bought 2 gallons and poured them both through.

    > 9) Make sure you put in as much total as you drained out.  Then
    > reconnect the hose and clean up.  You just performed a $90 service for
    > $20 -$30.  If you can change your own oil you can do the flush is was
    > pretty easy.

    > If you don’t have  a drain plug. You have 2 choices.  1)  Follow the
    > instructions above just don’t drain pan.  You’ll be mixing new fluid
    > with the old fluid in the pan so it may take more fluid to run clean
    > but anything is better than nothing.  2) Suck out the fluid through
    > the fill hole.  There are some systems out there for this.

    > http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=45403

    > Finally if you insist on dropping the pan I have 1 phrase that will
    > save you a lot of time.  "Permatex The right stuff for imports"  This
    > stuff is great.  I came across it in another post.  Here is what I
    > did.  Remove the old gasket.  I used scotch bright to clean up both
    > surfaces.  Then I put a thin bead of this stuff all around the pan.
    > Make sure to go around all the bolt holes.  Then put the pan on with
    > this stuff still stickey.  Tighten the bolts to finger tight with
    > wrench.  So just snug them no real torque.  Wait a day.  Then torque
    > bolts to spec.  I did this and have no leaks.

    > Good luck.  My next project is to replace the AC compressor on my
    > mothers Honda.  I’ll post what I find if it works.

    Excellent post! There’s a similar posting done by me on the Toyota
    Trucks newsgroup. I’ve done this very procedure on my 1995 T100
    several times and it has 349,000 miles with the original auto.
    transmission.

    One thing I did differently: When the engine is started and the trans
    pumps out two quarts of fluid, I shut off the engine and emptied the
    catch container. I then put in two quarts of new fluid, restarted the
    engine and repeated. It took 10 quarts for the output color to match
    the input color.

    In my opinion, this is the most important maintenance you can do to
    ensure long A/T life.

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