ATF drain and refill how many times?

[tiredguy]

Hi

I just got a 2000 VW Passat from my sister.

ATF has never been serviced.

This past weekend I drained about 4 quarts of dark black atf and replaced with Valvoline MaxLife. The vehicle holds about 9.5 quarts total (includes torque converter and atf cooler).

How many more refills should I do to dilute the old fluid to an good point? Also how long should I drive after refill until draining? Basically how long does it take for the new fluid to mix with the old?

Thanks

 

[thastinger]

That would depend on the % of system capacity you can drain out of the pan.

 

[SC Maintenance]

I would run it for a while. Maybe again in a few months.

If you want a full flush you can do a poor man’s flush out the cooler return line if it has a cooler.

 

[Kira]

How many miles on your 26 model year old Passat?

With my experiences, I was going to suggest a week between drain & fills.
People here will warn against slamming the system with all new fluid at one time.
If you drive every day, you could make it 3-4 days if you wanted to. The fluids mix almost instantly.

I'll disagree with SC Maintenance regarding waiting a few months between d&fs.
You want to get the fluid clean in some kind of timely manner, yes?

Also, with my experiences with this, you may see the "dark black" ATF becoming more transparent red after the third d&f or the fourth.
Or improvements may not be linear. If it stays real dark after 4 d&fs, leave it a week so any cleaning / dirt suspension can take effect.

May I suggest you retain a sample at each d&f so you have more than your memory to chart your progress.

Also, did you research that MaxLife (DexMerc LV, I assume) was a good substitute fluid? just askin'.
I've used lots of the stuff in vehicles other than your era VW.
Maybe a quick search on a VW board will reveal a preferred substitute.

 

[tiredguy]

That would depend on the % of system capacity you can drain out of the pan.

draining removes 43% of the system capacity

 

[SevenBizzos]

Yeah, that's been in there awhile. In this case, I'd do the three to four D&F's in a short window.

 

[tiredguy]

Yeah, that's been in there awhile. In this case, I'd do the three to four D&F's in a short window.

what is a short window?

 

[GW.]

If it’s never been done I do it three times. Take a 10 min drive between each. Fluid should look much cleaner when completed.

From there on out do 1 drain and fill every 25-30k to maintain.

 

[JeffKeryk]

what is a short window?

A few days is more than enough. I would service that transmission one more time now and then at next oil change service.

 

[thastinger]

draining removes 43% of the system capacity

I've been able to do full fluid exchanges on all of our vehicles by locating the fluid return line to the transmission from either the heat exchanger or the radiator. Drain the pan into a container that tells you how much you drained out, pour that amount back into the transmission fill. Remove the line to the heat exchanger, pump out the same amount you put into the pan(help to have a second person to start/stop the engine). Rinse and repeat until you have reached maybe 1 Qt more than the total system capacity.

 

[SevenBizzos]

what is a short window?

Something like 50-100 miles. You just want it to blend all way in and do that at temp (this one is my preference).

 

[Furious]

Black fluid is not typically a good sign for the overall health of the transmission, it is possible drain/fills could actually hurt it further.

But if you are going to continue the drain/fill route do it until the fluid comes out nice and red then from there go to regular maintenance intervals and pray.

 

[GI_GRIFF]

Hi

I just got a 2000 VW Passat from my sister.

ATF has never been serviced.

This past weekend I drained about 4 quarts of dark black atf and replaced with Valvoline MaxLife. The vehicle holds about 9.5 quarts total (includes torque converter and atf cooler).

How many more refills should I do to dilute the old fluid to an good point? Also how long should I drive after refill until draining? Basically how long does it take for the new fluid to mix with the old?

Thanks

Years ago, I took a Dodge I owned into a BG find a shop place that had the transmission flush equipment and had it done. It worked great! That service will completely remove the old fluid from the whole system, torque converter and all, then they run some kind of cleaner through and ultimately refill with new fluid. Not all the BG shops offer the transmission flush service; they don't have the equipment; you would have to call ahead. Anyhow, it worked for me.

https://bgfindashop.com/shop-locator/

 

[duck__dodgers]

either do it by eye, or do the math.

say (these are not the numbers for the Passat)---you only get 75% out per drain. so (1 - 0.75) = 25% of the oil in the pan is old. so two drains is 0.25 * 0.25 = 0.06. 6% of the pan has old oil after 2 drains. 3 drains: 0.25 * 0.25 * 0.25

 

[MasterSolenoid]

May I suggest you retain a sample at each d&f so you have more than your memory to chart your progress.

I would do this.
Get some (clear glass) baby food jars.
Label them with Date and Mileage.
Nothing better than seeing your progress.
And have one jar with "new' fluid for comparing.

 

[jtwrace]

ATF is an incredible cleaner. Once you drive it at operating temp 10 miles, drain and fill it again. Do this until the fluid is all red.

 

[Bullet]

I recently did a filter change and refill. Ran it a few minutes (it was off the ground) and did a drain and refill. Repeated until I went through 4 gallons.

 

[JTK]

..How many more refills should I do to dilute the old fluid to an good point? Also how long should I drive after refill until draining? Basically how long does it take for the new fluid to mix with the old?

Thanks

Assuming you get ~4qts out per drain/fill, like the other say, I'd feel pretty good after the 3rd drain/fill. Obviously, drain/fills aren't the most efficient means to change ATF, but it tends to be the least expensive depending on which fluid you choose and it's easily DIY do-able. Keep in mind you may never get the fluid to look "new".

I know with the GMs in my sig with the 6AT, I can never get the ATF to look clear, cherry red. It's always dark in them. The one GM 9AT I own (Traverse) did clean up pretty well after 3 d/f's.

 

[Kira]

There you have it tiredguy, a fluid framework on which to structure your own guesswork.

Multiple d&fs will get the fluid cleaner overall.

Driving between d&fs gives you the REMOTE POSSIBILIY to feel a change.
I agree with getting the vehicle up to temperature a couple of times over a couple of days.
Maybe, if done entirely, you'd feel the effect of the new fluid's lubricity.

All of us here can only go on experiences we can recall or have read about.

The caveats over hurting a transmission further are way overstated.
The warning was that fresh fluid would dissolve crud which helped seal the servos' pistons.
A more solid observation is that vehicle owners would wait for some off operation of the transmission, then refresh the fluid, which would "worsen matters"
Here the units likely just shifted harder (faster) due to better lube. Any excess wear during its harsh service life will be spotlighted.

Moral of the Story: Don't let your fluids get foul in the first place.

+1 on not reaching new fluid clarity.
However, if, after 3 you're not satisfied (gut), you'll be in as good a position to decide your future as anyone here.

 

[SOUNDMAN5000]

On a 25 year old car that the fluid had never been changed I would have not changed it.
I didn't always feel this way but I have seen transmissions fail right after a fluid change on cars that had never been or were over due transmission service...
However, Now thats its been changed I think I would keep flushing or changing a few times till all fluid was clean and bright red.
But I am far from a expert.