ATF 3x Drain & Fill

[Supermanclark]

Before everyone starts bashing me, I'm not here to ask opinions on whether or not I should be "flushing" the transmission fluid. I am only asking how it should be done when I do it.
I bought enough fluid to flush out all the old fluid by doing a 3x drain & fill.
How would you go about changing it this way?
Do I need to plug the drain hole every single time I add more fluid into the top?
I don't believe I would be driving the van in between changing either. The goal is to avoid mixing the new fluid with the old fluid, right?

 

[Bill7]

Before everyone starts bashing me, I'm not here to ask opinions on whether or not I should be "flushing" the transmission fluid. I am only asking how it should be done when I do it.
I bought enough fluid to flush out all the old fluid by doing a 3x drain & fill.
How would you go about changing it this way?
Do I need to plug the drain hole every single time I add more fluid into the top?
I don't believe I would be driving the van in between changing either. The goal is to avoid mixing the new fluid with the old fluid, right?

In the Honda owner's manual for my Honda Odyssey's, it mentions a 3 times drain/fill, but aludes to doing it 1 more time (for a total of 4 times). Its good to drive the car at least 100 miles in between each drain and fill so the new fluid mixes with the old. Otherwise you could drain out the new fluid you just put in.

I usually do a 4x drain and fill with each used Honda I buy.
Then, after that, I do drain/fill's every 15k miles / 3 years whichever comes first..
The odyclub forum mentions that if you do that, you're golden, and likely will never have a transmission problem in the future.

 

[dubber09]

If the goal is to avoid mixing new and old fluids (as much as possible) then you do a drain and fill, then remove ATF cooler line going into ATF cooler from transmission and with a longer hose attached and running into a bucket you start car and let a quart of ATF out, stop the engine, measure ATF volume that came out and add same volume, repeat till only fresh fluid starts coming out.

 

[labfan]

It's all unnecessary to be frank but i don't fault you for being more conservative than not when it comes to maintenance.

I have about 334k on my all original internals 4l65e since new. Always did regular spill and fills about every 2-3 years. No real need to do any of that unless you're trying to prevent further neglect. But yes you can remove the cooler line and pump it out. There are many videos on youtube and they're all the same. No need to frequently drop the pan and change the filter. Those are good for at least 100k.

 

[SwampSurvivor]

I've just done multiple drain and fills in a row. Drain > fill > Run engine (or put in gear if it doesn't run the pump in neutral) > Drain > fill.

I did this recently with our Nissan Sentra. There were a few miles in between, but otherwise multiple drain and fills in succession

 

[Furious]

Well for one I highly recommend against using a shop fluid exchange service, the machines they use are not properly cleaned and often times incorrect fluid is left in them.

The best DIY method if you want a thorough flush is to do the cooler line method as mentioned above.

But if you just want to get the majority of the old fluid out you can do multiple drain/fills.

Drain it, fill it, run it for a few minutes through all the gears, repeat 2-3 times, and yes you would need to plug the drain hole so use the old drain plug gasket until the last drain/fill.

You will be mixing the old fluid with the new with a drain/fill method that is just how it is there is no getting around that.

 

[John105]

Not sure if folks understand why 3x but that’s conventional wisdom. The reason is you cannot drain all, nor even the majority of the fluid out. So you are taking old fluid out, and mixing in new, and diluting the old. This method will never get all the old out like we almost do with an oil change.

I have my official Toyota doc somewhere for my LS430. But it went something like this. The number is how much old is left.

1. 55%
2. 27%
3. 19%

This is a specific vehicle but Toyota felt if first drain/fill done timely, then 19% old left behind is all that’s needed. #4 was like 11% I think. If my numbers are right that’s what I read in 2016 but you get the idea

 

[Supermanclark]

But if you just want to get the majority of the old fluid out you can do multiple drain/fills.

Drain it, fill it, run it for a few minutes through all the gears, repeat 2-3 times, and yes you would need to plug the drain hole so use the old drain plug gasket until the last drain/fill.

You will be mixing the old fluid with the new with a drain/fill method that is just how it is there is no getting around that.

This will probably be the best option for me honestly...
I'm not against it, but could someone explain to me why you need to run the engine and cycle through the gears in between???

 

[kschachn]

This will probably be the best option for me honestly...
I'm not against it, but could someone explain to me why you need to run the engine and cycle through the gears in between???

Because when you add fluid it will go down to the pan or bottom of the transmission. If you drain it immediately you'll only be draining the fluid you just added. You must mix the new fluid with the old. It doesn't take long, just a few minutes of idling is sufficient for mixing.

 

[John105]

This will probably be the best option for me honestly...
I'm not against it, but could someone explain to me why you need to run the engine and cycle through the gears in between???

You want the new to mix with old…my independent garage actually would drive around the block a short distance…I guess the problem with that is the heat. ATF defies logic on how much the volume changes with temp…

 

[Supermanclark]

You want the new to mix with old…my independent garage actually would drive around the block a short distance…I guess the problem with that is the heat. ATF defies logic on how much the volume changes with temp…

Okay... I'm with you now...
I've heard other people say to drive hundreds of miles in between, but I'd much rather go about it the fastest way...

 

[nwjones18]

I started maintaining our CRV around 100k miles and I just did a atf change every time I changed the oil for the first 3 oil changes, now I plan on doing it every 3rd oil change or so going forward.. Its an easy time to do it on the CRV at least. I change the oil every 10-12 months.

 

[atikovi]

But yes you can remove the cooler line and pump it out.

Don't know what year car OP has or what part of the country, no way would I be disconnecting hard lines on anything over 10 years old unless in a southern state.

Drain and refill, drive for 4-5 miles, repeat 2 more times. If it was real dirty, might need a round four. The goal is to get it looking like this.

 

[JRHAWK9]

Don't know what year car OP has or what part of the country, no way would I be disconnecting hard lines on anything over 10 years old unless in a southern state.

Drain and refill, drive for 4-5 miles, repeat 2 more times. If it was real dirty, might need a round four. The goal is to get it looking like this.

View attachment 152737

A master Toyota tech would disagree with you.

 

[atikovi]

A master Toyota tech would disagree with you.

What part of what I said would he disagree with? If the fluid is dark, replace it until it looks like what comes out of the bottle.

 

[JRHAWK9]

What part of what I said would he disagree with? If the fluid is dark, replace it until it looks like what comes out of the bottle.

If you watch the video he specifically addresses those who do back to back to back drain/refills till it's clean and why it's not a good idea to do it. One can actually do more harm than good by changing it too often.

 

[64bawagon]

The Cruze I just sold to my son had 103k on it when I got it. The owners manual gave 100k as the maintenance interval for a car used mostly for highway driving. The trans in this car is very easy to service. One 11mm wrench and the plug comes out of the trans. Drops 4.2qts that is then refilled via the cap under the hood. After the first spill and fill I went through the warmup process and checked the level via the plug in the left wheelwell. Once I established that the level was correct I drove it for a month and repeated the process replacing the volume of fluid that came out. I ended up doing it 4 times total with a month in between using Valvoline Maxlife full syn Dex. The car has never been happier.

 

[Supermanclark]

If you watch the video he specifically addresses those who do back to back to back drain/refills till it's clean and why it's not a good idea to do it. One can actually do more harm than good by changing it too often.

That's honestly just a myth... Maybe if you NEVER changed the fluid before in the life of the vehicle. It's fine, if you've been keeping it changed regularly. A lot of people change it when the transmission was already having issues to begin with and they claim the fluid change made it worse, but it didn't.

 

[64bawagon]

I do know that DexVI may not always stay bright red but can still be perfectly serviceable. The early Transynd from Castrol was like that. Its been a while but I believe that Allison had a bulletin on it at one time. (I have been out of the game for a while now "retired")

 

[atikovi]

If you watch the video he specifically addresses those who do back to back to back drain/refills till it's clean and why it's not a good idea to do it. One can actually do more harm than good by changing it too often.

If you mean the part where he says if the car has over 100,000 miles on the original fluid, don't change it now? You believe everything you see on the internet? That may have applied 20 or 30 years ago, but not today. Transmissions are built different now internally.