Multiple AT drain and refill a waste of money.

[WhizkidTN]

Originally Posted By: Kira
I agree. But do a drain & fill first THEN go straight into your cooling line pump-out.
This way the transmission will be sucking up nothing but clean fluid. You won't be adding clean fluid to a half emptied sump.

EXAMPLE: Pump outs usually recommend pumping out 2 quarts-shut off engine-replace the 2 quarts-restart engine and pump out 2 more-shut off engine-replace the 2 quarts etc. This is recommended so you don't suck ait into the system.

In my case the sump holds 4 quarts. I'd be pumping out 2 and adding 2 new quarts to dirty fluid.

Starting with a fresh sump makes it a more efficient process.

The argument against wrestling with stuck cooling line fittings wasn't mentioned. If things are super crusty and old, a succession of less efficient drain & fills can make sense.


I used to do this on several of my cars. I had added a Magnefine trans filter in the cooler lines so it made it easier. Over time, I felt that just doing the drain/fill a couple of times (with ~100 miles in between) would be fine.

What ever you do, NEVER let the trans pump run out of fluid while running (I was super careful about that) if doing the cooler line method.

FWIW: There are some good arguments for doing the simple 1x drain/fill to reduce the chance of "shocking" the tranny with detergents and causing debris to come loose and plug up some fine mesh screens. I personally was a victim of the Trans-Flush machine and their special cleaners doing just that. Within a couple of weeks, the transmission died an untimely death and had to be rebuilt. NOT fun.

FWIW2: Some cars also want an internal ECU (TCM?) counter reset when you totally change out their fluid (Volvo's for example). Makes a big difference in shift quality.

 

[Ethan1]

Originally Posted By: MichaelRS
But what I haven't heard anybody point out, maybe because it's so obvious that it's not necessary


I think you're on to something there. If we look at this from the flip side, did anyone ever think that the worn-out molecules were pushing and shoving, eager to be the first ones out of the drain plug? No, they did not.

 

[KrisZ]

Originally Posted By: RevelationLion
Pull the cooler line and exchange most of the fluid without wasting fluid and money.


Bingo!

D&F is fine if the cooler line access is not great, but otherwise I'd rather do one complete cooler line exchange, than mess around with periodic D&Fs, as the name of the game is getting rid of ATF contaminants, not refreshing the add packs.

 

[SirTanon]

Originally Posted By: MichaelRS
Thanks SirTan. That's interesting. You said yours was kind of a purplish red where did the Purple part come from? Is it Royal Purple ATF?


No - I don't use Royal Purple products. Too expensive. It's actually a mix of what's left of Motorcraft Mercon LV (from years ago), and Valvoline MaxLife ATF (which is what I have been using for the last few drain&fills), both of which are bright red going in.

The reason it looks purple-y is because Mercon LV tends to darken and turn kind of purple-y as it wears/ages. I'm assuming that Valvoline MaxLife ATF, since it's is deemed Mercon LV compatible, also exhibits similar behavior as it ages.

Keep in mind, all fluids darken as they age, and the 6F35 tends to be rough on fluid. In this case, instead of going brown, LV goes more.. purple-ish.

 

[MaximaGuy]

ATF replacement is cheap (in-fact very very cheap) insurance for a expensive transmission.

If a vehicle has the bells-whistles to drain and replace do it based on your comfort level (30K is reasonable).

I haven't heard off a transmission going bad ever - even without changing fluids.

ATF is cheap, why not replace it.

 

[MichaelRS]

Yes. According to the records the original owner did a full flush at 28,xxx and 47,xxx through dealers, originally in illinois and then again here in OC, CA. The dealer out here even has notes about the B&G flush kit used.
But I have no records indicating any transmission service from that 47k until I got it at 136k in 2012.

That is when I had my mechanic drop the pan and change strainer. There was little to no smudge or any other kind of debris in there at that time and the filter was pretty clear as well.
We refilled it with Max life. And now 42k later, I sucked out and replaced the fluid, 2 qrts at a time for 3 times, with approximately 150 miles between each procedure, again with Maxlife.

I'm not dropping the pan just now because I'm not in a position to do it myself and due to some other expenses I'm not able to afford it right now through a garage.

 

[MichaelRS]

Thank you, Egghead, I certainly like your numbers better than mine.

 

[MichaelRS]

Forgot to mention, and I ran out of time to edit, after doing what I've just done I plan to drop the pan and replace a strainer again at 200,000 miles. 22k from now.

 

[MichaelRS]

Originally Posted By: KrisZ
Originally Posted By: RevelationLion
Pull the cooler line and exchange most of the fluid without wasting fluid and money.


Bingo!

D&F is fine if the cooler line access is not great, but otherwise I'd rather do one complete cooler line exchange, than mess around with periodic D&Fs, as the name of the game is getting rid of ATF contaminants, not refreshing the add packs.


I would like to do that as well. But f you see my prior post and the known service history on my transmission I wonder if that much new fluid at once would be too shocking to my the system In my case.
That is what my mechanic wanted to do but I was a little afraid to for all the reasons that you here out there.
Also, with that kind of service I'm sure you're talking about apan drop and screen replacement.
Again, I'm on a fixed income and not able to divert the money for that at the moment. But $40 to drain from the cooling lines I can do.
Still I would like to wait because between the pump I got and the fluid recently I've already spent $75.
I know it doesn't sound like much, but it kind of is when you're on a low fixed income.

I have also heard that flushing is fine, IF that is what you started doing from when the car was new and you keep up on it.
Anyone have any BAD experiences with flushing under those conditions?

 

[Artem]

Originally Posted By: KrisZ
Originally Posted By: RevelationLion
Pull the cooler line and exchange most of the fluid without wasting fluid and money.


Bingo!

D&F is fine if the cooler line access is not great, but otherwise I'd rather do one complete cooler line exchange, than mess around with periodic D&Fs, as the name of the game is getting rid of ATF contaminants, not refreshing the add packs.


Never understood doing multiple drain n fills on auto transmissions. Why replace only a small portion of the fluid and leave a bunch of the old stuff still in there to continue degrating and contaminating the new fluid?

I've been doing the radiator cooler lines flush for years and have done many old cars with BAD fluid. No issues. I always let the car idle for a good half an hour after the flush to let the transmission slowly pump the fluid around and around and clean things up without crazy pressure. Then I take it around the block and go slow to let the clutches wear in to the new fluid. Then I let her rip to redline in a few gears while getting on the highway. I've done many cars with 200k+ and still going strong. I service them regularly. They all shift much smoother.

 

[DoubleWasp]

Whatever type you do, always get that pan clean. Those pans can really build up some crud on older transmissions.

 

[JTK]

How is it ever a waste when you are reducing the amount of contaminates AND refreshing the add pack in an oil lube system?

Obviously a cooler line transfusion (when can be safely/effectively done) will achieve more of the above with less fluid required, but both achieve the same end game.

After all, we're BITOG. We make some of the best used and salvage drivetrains known to man.

 

[Artem]

Originally Posted By: JTK
How is it ever a waste when you are reducing the amount of contaminates AND refreshing the add pack in an oil lube system?

Obviously a cooler line transfusion (when can be safely/effectively done) will achieve more of the above with less fluid required, but both achieve the same end game.

After all, we're BITOG. We make some of the best used and salvage drivetrains known to man.

Well said on all accounts really but that last line is EPIC.

 

[Hall]

Originally Posted By: Egg_Head
For the OP, here is the transmission drain/refill replacement ratio for his example of replacing 1 qt. in a 4 qt. unit:

(snip)
#6 82.20%
#7 86.65%
#8 89.99%
#9 92.49%
#10 94.37%
If one continues doing the math, it will never reach 100% either. Personally, get it above 75% and sleep easy....

 

[Hall]

Originally Posted By: eljefino
Your math is right but is also accounted for by the engineers.

People try to out-think this...
I know I'll be crucified for saying this, but if the engineers say replace "x" at "y" miles, for the vast majority of cars, this is perfectly valid. Yes, components fail prematurely, but it's highly unlikely that changing the fluid, using this thread as an example, will change that.

 

[JTK]

Originally Posted By: hallstevenson
.. know I'll be crucified for saying this, but if the engineers say replace "x" at "y" miles, for the vast majority of cars, this is perfectly valid. Yes, components fail prematurely, but it's highly unlikely that changing the fluid, using this thread as an example, will change that.


Crucify no. Agree? Probably not. Having participated in vehicle forums for 18yrs or so, I've seen too many examples of transmission failure due to lack of maintenance. Some examples are the Ford AX4S/AX4N, GM 4L30E and Mitsu/Hyundai F4A51. Folks would routinely post, complaining about "early" failure on these units, while having never changed out the black, thick and nasty ATF in them. People who did do ATF changes at some point got 2-3x the lifespan.

 

[Donald]

Originally Posted By: MichaelRS
In researching about how to service my own transmission on my 2002 Toyota Sienna I naturally came across the drain and refill method. And what I noticed from some of the post was that people would drain their transmission then fill it then drive it for x amount of time and drain and refill again and they may do this two or three or four times. Obviously the idea being to get as much fresh tranny fluid in there as possible.

But what I haven't heard anybody point out, maybe because it's so obvious that it's not necessary, then again maybe it's not so obvious, is the waste of good transmission fluid using this method. Let me just give an example to show what I mean.

For the sake of argument let's say your transmission holds 4 quarts. So you drain out 1 quart and then you put in 1 quarter of fresh. Your transmission fluid now has 25% fresh fluid in it. Now you drive your car around for a couple of days to mix up the old with the new fluid and then you drain off another quart. Unfortunately you're not just draining off old transmission fluid now. 25% of that fluid you are draining off is the new fluid you put in there. So when you add your new quart back in you're not adding a full quart of new fluid to the old, for now a total of 2 new quarts in your system, you are replacing that 25% of of a quart of the new fluid you just drained. And now only 75% of that from quart is new fluid in your system.

Therefore your transmission does not have 2 new quarts in it for 50% new in this 4 quart system after this second drain and fill, it has 1.75 new quarts. And I think that give you 37% new.

Then you repeat the procedure for a third time and now you're draining off yet more new (37%) transmission fluid from the last two days procedures and the one quart you now put in has to replace that 37% and then the 63% that is old.

And it goes on and on like that to where each time the precent of the new transmission oil you are draining out, and throwing away, is a greater and greater percentage.

My own car holds about 8 quarts total. The math I did for it told me that if I wanted to achieve a 75% freshness rate of my transmission fluid using the multiple drain and refill method, assuming I did 2 quarts at a time, I would have to do that 10 times. In other words I would have to use about 20 quarts to get 6 quarts worth freshness in the system.

And I use 2 quarts for my example because the suction pump I got is only able to get out 2 quarts at a time. But the math carries out, Each time you drain and refill you're taking out X% of the fresh fluid you put in from the prior procedure(s).

And drain and refill once every 30000 miles?
That means that at 30,000 miles X percent of your fluid will be fresh and x percent have 30,000 miles on it.
Then you do that again at 60,000 miles you have X percent that is fresh, X percent with 30,000 miles on it and X percent with 60,000 miles on it and so on and so forth. That all doesn't sound good to me.

Of course a lot of this falls under the better than nothing category, especially if you do not have the luxury of owning the car from new and starting a proper service schedule and method. And then it seems that draining as much as you can in one sitting is the better way to go. Like from the cooling lines.

Ok. Just putting this out there as a bit of consciousness raising. If my theory is wrong please tell me. I would very much like it to be.


It depends on whether you want a total exchange of the ATF or just refresh the ATF.

A DIY cooler line exchange is easier than many think. And it wastes maybe 1 qt.

 

[blupupher]

If you don't see a reason to do a partial exchange, then don't.
If you do, then do it.

Me personally, I have had shifting issues fixed by partial fluid changes, so I do not see how it wasted any money.
On vehicles I buy new, I do drain and fills every 30,000 miles and a filter change (if it has one) every 60,000. To me that helps keep the fluid "fresh" and drain out anything that may have broke loose.
A few times I have even installed an inline filter (neither current vehicle has one now, really need to get around to that). I have always wanted to do a true filter setup, but never have. If I ever actually tow on a regular basis, I would.

 

[KrisZ]

I love the engineers know best arguments. These mythical creatures, same as scientists, are incapable of making bad decisions and impervious to the outside influence.

 

[DBMaster]