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2000 OB Auto
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Discussion Starter #1
Hi,

First disclaimer this is not for my subaru but my wife's car (04 sienna V6) but our forum is way better than toyota's. People here are much more mechanically knowledgeable and also better with hands.

The car has 190k+ miles on it. Never has ATF changed before. We were ignorant and believed there was no need to change ATF.

Now I want to change it. There are two schools of thoughts that I searched. 1, flush (DIY with cooler return line) and 2, drain/fill multiple times. There are another two schools of thoughts on the replacement of screen filter, change or not change.

Personally I would prefer to flush myself. This saves money because I only need to buy the actually amount (plus a little more), it gives me ~99% new fluid, and we do it just once. Three benefits.

But there are horror stories about trans die after they flush, within 1000 miles.

I cannot comprehend why this could happen if done right. I would think the misfortunes are due to people are not doing things right (like done at shops or dealerships) where they may mix different types of ATF (not cleaning machines) or other poor practice (e.g. maybe disturbing the metal shreds too much). (My bad experiences with shops is the sole reason I started learning to work on cars myself.)

But this is just my thought. I wonder if there is true mechanical reason not to flush an old car like this which has never had ATF changed before? Is it safe?

Also the screen, which ever way I go with ATF, should I change it?

Thanks in advance!
 

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Lawn ornament XT
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14,366 Posts
I recognize two ways a flush can be harmful to a never-serviced old transmission:

1. Seal conditioners. One of the ingredients in ATF is a substance that helps keep rubber seals pliable longer. You're about to refresh that chemical, and that could stop leaks or start new ones. It'll be hard to predict where & whether it's significant, but the point is it will be a change from what you have now.

2. Detergents. New ATF will have a lot of detergent in it, and after you swish it around through there in the days after the flush it could loosen up some garbage that has been safely glued to the inner walls for the past 19 years. If a big bolus of it breaks loose and blocks a passage or prevents a valve from closing, you could have real trouble.

I feel that problems attributable to either of the above are pretty rare. I would take the risk, personally. Mine shifts a lot better with fresh juice in it.

I do partial-volume drain & fills both out of convenience and the sense that a gradual replacement will smooth out and mitigate the above effects.
 

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I simply cannot abide useless people.
2006 2.5i and 2002 3.0 wagons.
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12,306 Posts
On an old unit that has never been serviced, I would not flush. Too high a potential for problems listed above.

I would go with a few drain and fills with some usage between each, including manually putting the vehicle in each gear. Is it slower? Yup. Is it more wasteful? Yup. Does it have lower potential to cause system shock problems listed above? I believe so.
 

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On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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26,305 Posts
what fluid does a toyota van like this take.?

does it have a dipstick?

how does the fluid look thats in it now?

have you had it for all these years and all these miles?
 

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2000 OB Auto
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Discussion Starter #5
Thank you @rasterman, @AWDFTW and @eagleeye! I guess I will take the safe route and drain/fill with some driving in between. If the car breaks down, even if small chance, I may not hear the end of it.
@eagleeye
This van uses Toyota's Type T- IV ATF. I will go with this. Pretty sure there are others compatible.

It has a dipstick. The color does not seem bad. It is not particular red but not black either. Please see the picture. Given the age this might be decent. Also there is no loss of fluid either seen from the mark.

We bought this car new. Just didn't take good care of it. Next have to tackle oil leak.
 

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06 OBW 2.5, 05 Forester, had 03 H6 OBW
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I have a hand-pumped suction tool to do it from the top, I much prefer doing it that way!
 

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2011 Subaru Outback 2.5i Limited
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Great advice in this thread - good work guys!

My experience from another incredibly skilled forum for grand prix is similar to the above.

Check fluid color and smell. If it is dark or smells "burnt", changing the fluid in any manner could spell trouble. Your fluid appears to be just slightly discolored but not necessarily dark. Give it the smell test.

My understanding from many accounts I've read about is something like this. Even if your trans is working, if you have compromised fluid that has already caused damage to the transmission, clutch plates or has varnished the inside of the trans, nothing good can come from adding new, ultra slippery new fluid with new detergents. There can be a bunch of clutch material in the fluid that is still allowing the clutch plates to function and once you flush out that fluid (and all the clutch material in it) the clutch plates won't have enough friction to function anymore. Or as mentioned above, a shock or new detergents and other additives may break something loose that was functioning fine before.

I'd have to agree with the suggestions above and your decision. Do periodic drain and fills to ease into the new fluid. I'm thinking first drain and fill right away, then maybe every 5,000 miles? What interval would you guys think on the drain and fill intervals?

After you do 3 or 4, you could assume your trans has been cleaned and if it's performing well, consider doing and system flush with the return line at your next change.

Great question, great content in here! Let us know how things go!
 

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Master Caster
2005 XT, Mildly Modified...2006 XT Limited, Highly Modifed
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I'd have to agree with the suggestions above and your decision. Do periodic drain and fills to ease into the new fluid. I'm thinking first drain and fill right away, then maybe every 5,000 miles? What interval would you guys think on the drain and fill intervals?

After you do 3 or 4, you could assume your trans has been cleaned and if it's performing well, consider doing and system flush with the return line at your next change.

Great question, great content in here! Let us know how things go!
The 1st time, drain anytime after say 100 miles or at the next oil change. I do mine every 7K to 11K miles ... drain and fill. Every 2-3 oil changes for me. I did the 2006 more often side of that, it has mole miles on the transmission...more like every 7K miles.
 

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I do drain-and-fills every 30,000 miles. I believe that flushing is far riskier. It can drag long-settled debris up through the valve bodies and cause problems that were not there before. I have never flushed a transmission and never will.

Drain-and-fills on a 30,000-mile interval have worked for me for more than 40 years now. We typically keep our vehicles until 120,000 to 130,000 miles before I sell them to the next owner. I have yet to experience a transmission failure.

Just be sure to use ATF that meets the required specs, and follow the proper procedures. Most automatic transmissions are easy and relatively inexpensive to drain-and-fill yourself. A typical drain-and-fill will remove/replace about half of the system's ATF capacity. Start doing that at 30,000 miles, do it every 30,000 miles afterwards, and that schedule will probably keep your transmission in good health for as long as you choose to own your vehicle.
 

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2011 Subaru Outback 2.5i Limited
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I'm not sure everyone is reading your post. Since you're already at 190,000 miles on the original fluid I would drain/fill as soon as you can and then do probably 2 or 3 more drain and fills at intervals of maybe 2-3k miles. At your average miles per year, you should have mostly new fluid within the next year. As someone mentioned this should help reduce the possibility of shocking the system with instantly new additives and detergents. Hopefully, introducing the smaller amounts of fresh fluid (and it's additives) will slowly remove contaminants to be removed at the next pan drop. Also, this will give you and an opportunity to gauge performance changes. If you end up with better performance and smoother shifts, you're probably moving in the right direction.

There is a difference between a power flush that you'd get at a garage, and a "flush" that a DIYer would do at home. The home method simply involves catching waste oil from the return line while ensuring the fluid level in the pan stays within a safe zone - usually utilizing a series of starting the car purge, stop, refill pan to get the job done.

I've done pan drops and a fluid flush at home all with good results.

Good luck on your endeavors!
 

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2000 OB Auto
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Discussion Starter #11
Thank you all for your great inputs!

To CNY_Dave, what is the benefit removing the ATF from top vs draining?
 

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'14 Subi OBW, '18 Subi Forester
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There are two active Toyota Sienna forums, both under the AutoGuide umbrella. ToyotaNation has a sub board for the Sienna that get's limited traffic, and SiennaChat where I'm also a moderator. Toyota Sienna Forum - siennachat.com You can post future questions about your 2004 Sienna under the Gen-II Van section, and particularly for your case, under the Problems-Maintenance-Repair section.

About your van....

Your 2004 uses a U151E or F (FWD or AWD) transmission. It's set up for Toyota Type T-IV Transmission Fluid. This is an older, 'heavier' fluid meeting the JWS3309 specification. Don't let anyone sell you on the lighter WS used in the 2007+ vans. While it's the same transmission, the calibrations are different. Which in my opinion also says avoid MaxLife and other lighter fluids meeting the WS spec.

Toyota, per Tech Tip T-TT-0122-11 recommends the use of Flush Machines only in the event of serious grenading, and then only for lines and coolers. Not for preventive maintenance.

Other doc's I've seen express concerns about the use of the solvent cocktail with these recirculating machines. Cleaning a bit of varnish from close tolerance valve body components is good. Freeing up big chunks in not!

Agree with the gentle pan drain and replace 3-4 quarts procedure as a way of upgrading the additives package and removing some circulating contamination. You don't want to shock an old, unmaintained unit.

Your transmission should have a real filter that you might consider changing after some fluid changes loosen up some gunk and chunks. There was some discussion as to whether the 2004 vans use the Filtran filter with the Dacron microfiber element, but I believe that was settled by someone who replaced it.
 

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Thank you all for your great inputs!

To CNY_Dave, what is the benefit removing the ATF from top vs draining?
I know this wasn't directed at me, but removing from the top will likely be much less of a mess.

However, if you drop the pan you get some benefits: you can inspect any particles in the pan (clutch material, metal shavings, chunks of metal, etc) and get an idea of wear on the transmission, you can clean the pan before re-installation, and you can change the filter.
 

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2021 Outback Onyx Edition XT
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For what it's worth, don't go by the color of the ATF alone. Yes, if it's brown/black that could indicate problems... There's a Youtube channel by ChrisFix that cautions against ATF replacements after 200k+ because of dislodging stuck-on goop and it making its way into the VB. That being said, if you do nothing, you almost certainly will have a problem. A conundrum.

At least yours is easier to do than my CVT!
 

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2000 OB Auto
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Discussion Starter #15
@Fibber2, thank you. I am a member of siennachat and I see your posts many many times.
@stocker, I was thinking of dropping the pan for the last drain. Before that, just drain it. Yes I do agree it is less messy. Probably saves a gasket or two.
@CNY_Dave the suspense is killing me...
@Pilot1226 I will go check his video. Thanks!
 

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@Fibber2, thank you. I am a member of siennachat and I see your posts many many times.

Like certain diseases, I do make the rounds!!

Don't forget the special left handed doohickey shallow angle wrench you'll need to get to the pan bolts under the frame rail!
 

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Thank you all for your great inputs!

To CNY_Dave, what is the benefit removing the ATF from top vs draining?
It is hugely easier and no mess, so greatly increases the chance you'll actually do it!

If you want to do the 1st one with the plug to get anything in the bottom of the pan to flow out, it's still great on #2 and #3 and into the future to make it a lot easier.
 
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