Couple questions about doing a ATF line flush

[scott37300]

I was reading this thread, https://bobistheoilguy.com/forums/threads/atf-drop-pan-or-flush-with-135k-miles.106740/ and had a couple questions so I started a new thread since that one is old.

First question is how do I know which line to take off? Is there a way to tell by which line is higher or by where the line goes?

Second, it says to pump as much of the fluid out as you can. Is this bad for the transmission in any way to run it dry like that?

And last is should I be shifting threw the gears at all when doing this in order to "flush" the valve bodies out?

I have 2 cars to do this on(my other threads going) and was just going to do a pan drop and fill but think I will do a line flush if I can get it all figured out.

Thanks for your help guys and sorry for so many questions, just want to do it right the first time!

 

[Donald]

You can drive (not idle) the vehicle 15 minutes and feel both hoses. The cooler one is the return. If you have a drain plug by all means drain the fluid and refill before you start the flush. You use some clear tubing into a container and look for air bubbles. It will not hurt the transmission as long as you turn engine off ASAP. A second person helps.

Best is to do a pan drop, replace the filter, refill and immediately (do not start engine between) do a flush. You will have almost no mixing of old and new ATF.

The Amsoil website lists the pan and total capacity for all vehicles.

I am sold on Amsoil ATF. Expensive, but so is a new transmission.

Install a Magnefine and you will never have to drop the pan again.

A plain pan drop & refill only changes 1/3 to 1/2 of the total fluid. Good to refresh the ATF, but not to get rid of some old burnt nasty stuff.

 

[daves66nova]

Just do like i did. Disconnect any one line and hang over a pan,turn engine on and quickly turn it off. If you have quite a bit of oil ,that's the one you want.What i do then is turn on the car,let all the oil drain out,then quickly turn it off.I then add oil.I don't think overfilling at this time is going to hurt,since you will do the draining again.I kept doing this til the new oil came out from the drain hose.I then connected hose back on, refilled the fluid to where it's supposed to be.That's it.Did it all by my self.

 

[scott37300]

Originally Posted By: daves66nova
Just do like i did. Disconnect any one line and hang over a pan,turn engine on and quickly turn it off. If you have quite a bit of oil ,that's the one you want.What i do then is turn on the car,let all the oil drain out,then quickly turn it off.I then add oil.I don't think overfilling at this time is going to hurt,since you will do the draining again.I kept doing this til the new oil came out from the drain hose.I then connected hose back on, refilled the fluid to where it's supposed to be.That's it.Did it all by my self.


Do you drop the pan and change the filter first or when do you do that?

Thanks

 

[wiswind]

If you are going to drop the pan and replace the filter, I would do that FIRST.
Measure the amount of fluid that you get out......and refill with an equal amount of new fluid.
Now you are starting the cooler line exchange process with fresh fluid in the 'sump'.

When you remove the return line from the transmission, you run the motor at idle.....and shut it off when you start to see the fluid sputter (air bubbles in the fluid) or the fluid flow slows down.
MEASURE the amount of fluid that comes out of the cooler line....and add that same amount of new fluid to the transmission.
Repeat the cooler line exchange several times.....adding fresh fluid each time.

What is the make/model/year of the vehicles?

Also, make SURE to use a fluid that meets the specification that is called for in your transmission.
The correct fluid specification is often stamped into the transmission dipstick.

You can shift through the gears, but make sure that you do not neglect to keep an eye on the fluid flowing out.....
I would do so at the beginning of the 2nd cycle of cooler line drains......at the begining....with your foot FIRMLY on the brake, shift in to Reverse for up to 5 seconds and then back into park.
Then on the next cycle of cooler line drains......shift into one of the forward speeds or D, whichever is closest to Park.
Again, only for up to 5 seconds.
No need to shift into any other selections.....Park is same as neutral, except that Park has the parking pawl.
Some transmissions will go into 2nd when you select "2" but all the other forward settings will give you 1st gear when sitting still.
There is not much fluid at all in the individual gear select paths, most of the non-pan fluid is in the torque converter and the cooler / cooler lines.
So, you do not gain much at all from the gear select during the drain process.

Some vehicles have a quality re-usable transmission pan gasket that is much better than those cork ones that come with the filter kits.
If you have to replace the pan gasket, try to find a rubber one.....much better than cork.

 

[daves66nova]

Originally Posted By: scott37300
Originally Posted By: daves66nova

Do you drop the pan and change the filter first or when do you do that?Thanks
nope.It should be done but i didn't do either.I added an inline remote oil filter to use as an atf filter.

 

[scott37300]

Thank you for the detailed write up.

I am going to be doing this to 3 vehicles in the next month, grandma's 04 impala with 45,000 miles-has a filter and going to put maxlife ATF in it. Woman's 09 malibu 3.6L 6 speed with 50,000 miles on it-Chevy says "lifetime" fluid but going to change it and will probably use dexron VI just to keep the warranty happy, otherwise would use maxlife in that also. The malibu has no filter to change, just a drain plug on the bottom. And mom's 08 civic-honda says absolutely no flushing, just drain and fill and no filter to change and I bought the Z1 ATF fluid from honda just to keep the warranty happy.

 

[hate2work]

Scott, here is a write up with lots of pics from another forum on how to do a cooler line flush on a traditional auto transmission. This may give you some insight on what you need to do on the 04 Impala.

http://www.toyotanation.com/forum/showthread.php?t=325325

Also, here is a write up with tons of pics from yet another forum showing how to flush a "sealed" transmission. Your 09 Malibu probably has this type of transmission.

http://www.tacomaworld.com/forum/2nd-gen-tacomas/68462-diy-full-flush-automatic-transmission.html

And finally, the conventional wisdom is not to flush a Honda transmission, but just do as Honda suggests and do drain and refills. I have done as many as three drain and refills back to back on my daughter's 99 Civic, driving about 10 miles between drains to mix the fluid well.

Hope this helps, good luck

 

[scott37300]

Hate2work, thank you for those leaks, very nice pictures and step by step.

You say conventional wisdom is not to flush honda trans-just do the drain and fill like honda recomends. Why is this that it's alright to do a fluid flush on most vehicles but not on a honda? The 09 malibu is just a drain plug and fill from the top like the honda also, so is it ok to flush the malibu?

Sorry for all the questions but just trying to learn how to do these flushes or fluid changes right. Trying to weed threw the opinions and find facts since some say flushes are bad and some say they are fine. Sure would be nice to have one type of fluid and one procedure for flushing or filling!

Thanks again for everyones help.

 

[hooligan24]

i like to drain the pan(4qts out of the 9 the trans holds) and fill it it back up with the same amount I removed. I disconnect both transmission hoses from the radiator and put them into a milk jug that is marked at the 2qt mark. I have my GF start the engine to get the fluid pumping out, and when the fluid gets close to the 2 qt mark on the jug, I tell her to turn it off. I then pour in 2 new quarts of fluid into the fill hole and repeat the process 2 more times, equalling 10 qts total between the pan drain and the fluid flush.

 

[JTK]

Originally Posted By: daves66nova
Just do like i did. Disconnect any one line and hang over a pan,turn engine on and quickly turn it off. If you have quite a bit of oil ,that's the one you want..


It's best to have a helper/spotter for this task and make sure you have the hose in something substantial. Add an extender if you need to. I've done some that will pump out a gallon in a matter of 10sec.

Joel

 

[scott37300]

Thanks for all the advice everyone. Think I have the line flush down, will find out when I go to try it!

Still wonder why Honda says to just do a 3 qt drain and fill and why a line flush would be bad? But on a 09 malibu 3.6L 6 speed which has a drain plug and top fill also just like a honda people are saying to do a line flush?

So how do you know what transmissions you can line flush and what ones not to? Maybe I should start a new thread on this topic.

 

[wiswind]

If your transmission pan has a drain plug, then I would do a pan drain and fill FIRST.
This starts you off with fresh fluid in the pan, which is where the transmission fluid pump is getting the fluid from.
With the drain plug, it is easy.

If you do not have a drain plug, then you might want to skip the pan drain & fill as removing the pan is a bit more work.....that would be your choice.

Another thing, if you don't have a drain plug, some have been able to use a pump to pump the fluid out through the dipstick location.
However some transmissions may be easier to thread a pump hose down the dipstick tube than others.

If you don't drain the pan first, you might run a few extra quarts of fluid through during the cooler line fluid exchange.
In other words, if you have a fluid capacity of 10 quarts you might do the process so that you drain and replace 13 quarts of fluid.

Another addition that is nice is a Magnefine filter.
On a vehicle that has been driven more than a couple thousand miles, they recommend that the magnefine be placed in the cooler line that goes FROM the cooler TO the transmission.