elvenrider

I called a reputable mechanic (Recommended by many members in ClubLexus) to ask about a transmission flush for my 220k KM ES330, he recommended a drain and fill as a flush at this high mileage may affect the transmission negatively. He also stated that this is what is recommended by Toyota and Lexus.

For high mileage Lexus owners out there specially ES, do you agree with him or do you have other opinions? If you agree, do you think a drain & fill is enough to keep the transmission in a healthy condition on the long run?

WILLYumD

This is the widely accepted notion that I hear from dealers, mechanics, and forum users alike.

When a transmission is not properly maintained or very old, little bits and pieces have been shaved off (of the gears and clutch, I presume) and are floating around in the fluid.
These shavings can be a part of what keeps the tranny going. If you do a flush, you'll get rid of these shavings and the transmission won't have as much material to catch on (i.e. it'll slip).

Draining and filling usually keeps the shavings, so the transmission can continue to function.
Obviously not desirable, but it is what it is.

My 98 ES has almost 200k mi (320k km) and I have been told by multiple people to never do a flush on my tranny because it is so worn down (due to my dad's and my own neglect).
It's still running well, and I always keep the fluid in check.

PFB

The main problem with a flush is that all the new fluid does an excellent. Job of cleaning. This results in varnish being dislodged which subsequently could block small passages, resulting in transmission failure.

Bottom line is don't ever do a flush. Whoever says otherwise is giving you very bad advise.

tomf

This video explains the situation clearly and completely. Start at 4:52 to about 10:00 for the answer to your question.

elvenrider

Thanks, WILLYumD. That is reassuring, I will follow everyone's advice and keep my fluid in check with normal drains and fills.

elvenrider

Thank you PFB, now I understand why flushing is not recommended in my case. I am glad my mechanic insisted that I should not flush my transmission.

elvenrider

That was an amazing video. I watched it all and really liked it, it explained a lot and made everything clear. Thanks, Tomf.

speedkar9

As long as there's nothing wrong with the transmission, do a simple drain and fill.
Here's how that's done on the 4ES:

The transmission filter on the other hand, is much harder to get to, since the pan has to be dropped off. Two of its bolts are blocked by the subframe, which requires you to loosen the engine mount and lift the engine to get access. There's some discussion about it in the Camry forums on ToyotaNation.

elvenrider

Speedkar9, as usual very beneficial information. I saw the video and I am planning to follow it. And I will check the filter change procedure out. I think it is recommended to change the filter with the oil, right?

Oro

If you reviewed the video, it should be clear now why a flush is what you want to do. There is a terrible amount of speculative conventional wisdom out there on this subject, and that should have cleared it up. Here's a thread on how to do a proper flush on your transmission from the TN forum:

http://www.toyotanation.com/forum/10...lush-pics.html

Afterwards, use an extra quart to do your PS system:

http://www.toyotanation.com/forum/10...p-rebuild.html

Many of us use MaxLife as a synthetic replacement for the older tech factory fluid. Highly recommended. After establishing a clean fill, a 30k (mi) drain/fill interval is adequate.

tomf

It's not clear to me. Changing the fluid will not damage the transmission but in the case of burnt fluid (as discussed at about 5:30), flushing the transmission will remove the friction material potentially causing the clutches to slip. At 7:05 he says to check the owner's manual as to whether to flush or drain. At 8:40 he specifically covers replacing burnt fluid with a flush. He says it could potentially cause the blockages in the valve body.

My interpretation, in the case of burnt fluid, do NOT do a flush. Do either a drain and refill or nothing. I would do a drain and refill. In all other cases it doesn't matter if you do a flush or drain and refill especially if you have been changing the fluid on a regular basis. See his conclusion at 9:37.

elvenrider

Well, I had a different concolusion from the video. The video suggested that if you are not sure about the service history or the oil is in bad shape, it is better to do a drain or fill. A flush may cause the transmission to slip, if residues get trapped in this maze shaped part and got it blocked.
I checked my Lexus's tranny oil and it was ponk, but given the fact that the previous owner did not show service records for explicit flushes, I guess better safe than sorry and do drain and fill instead.

PFB

Smart choice.

LeX2K

No one seems willing to define what a flush actually is. From what I've read fluid pressure at the transmission cooler lines is about 40 PSI, in some areas of the transmission it can be 250 PSI. So unless you use a machine that exceeds the pressure of the transmission pump there is absolutely no harm in "flushing" a transmission. My method is remove the return line and direct it into a container, start the car and let the tranny pump do the work. Never had a problem.

Everyone and their dog seems to repeat the, "don't flush if the fluid is dirty" mantra but I have never seen one documented case of this harming the transmission. If the clutch pack material floating around in the fluid is the only thing keeping the transmission from slipping then the unit won't be lasting much longer anyway.

Either way replace your transmission fluid every 20,000 miles (all of it) and you'll never have a failure. Cheap insurance.

Oro

The best way to flush is to use the internal pump via the lines and not external pressure, as you described. And your pressure values are correct. I did a line pressure test on a transmission this summer (GM, not Aisin) and the values ranged from 48psi at idle in forward gears to a peak of ~265psi during shifts. Stall speed pressure is slightly higher, and that's closer to what would be going through the cooler lines -so something in the 50psi range would be correct for operating pressure of the cooler lines at crusing speed/rpms. Just like you said, it would take a lot of pressure to do damage.

Like you, I have also NEVER seen or credibly heard of a case were flushing the fluid then damaged a perfectly working transmission. Some people go get a flush when they start having problems, then like to try to blame that for the inevitable failure. And then their co-worker's nephew hears the story and then it's on Toyota Nation or Bob Is The Oil Guy...

To the OP:

My presumption was your transmission was working fine. Chris Fix is a talented video producer who monetizes his presentations, but not a mechanic or engineer. In fact, he describes himself as an "automotive influencer." Because of course, that is the authority to go to, right? Honestly, he is correct when he says at one point, "changing your fluid will never cause your transmission to fail." That's the comment he made that I should have referenced directly; I did not know he got confused and backed off it later in the video. But he is correct in that point because unintended crap IN the fluid is not going to influence friction adherence in a positive way. Chris Fix is far more reliable than some of the real idiots out there like Scotty Kilmer. The only youtube guru I have real respect for is Eric (the Car Guy), though I don't think he rebuilds transmissions. The difference between Eric and Chris is that Eric is using sound mechanical reason, logic, and coupling that with vast experience. Chris is more re-packaging what he's picked up. I guess that's the difference between a mechanic and an influencer. :

https://www.linkedin.com/in/chris-fix-451115a7

Let's take for example a high-mileage transmission with dirty or worn fluid, but an otherwise fully functioning transmission. Let us then drain out a small percentage of the fluid (~25%) and replace it with fresh - which is what a drain/fill does - what generally happens is that your fresh fluid will re-solubilize material that has fallen out of suspension in the dirty, over-loaded fluid. This material I am describing will accumulate in the bottom of the pan on these Aisin transmissions because they do not have a cellulose filter that captures it. You will quickly load that fluid back up and be right back where you were at the start in many cases. You have gone from having 25% clean fluid/75% bad in your transmission to being full dirty again in a week. And we haven't discussed the effect of sheer on the fluid and that 25% new isn't going to improve the overall viscosity of the sheered-down fluid much at all, so your increased wear rate won't be slowed down much.

The really best thing to do with a HM transmission of unknown history is drop the pan, clean it out, inspect or change the filter depending upon type (not necessary in these particular transmissions), and then correctly re-fill with compatible fluid, synthetic where available. Now you have a baseline established for maintenance and can be confident you didn't leave a real mess inside or just kicked the can down the road. Because that's all a drain/fill on a HM transmission is.

What some people will do - because it splits the difference between what is mechanically sound, cost effective and efficient and what is internet/cracker barrel folk-wisdom on the subject - is do 3 or 4 drain fills in a row, each a week or some other random time or mileage variable apart. This is about 85% as good as doing doing a flush at once. And it has the added comfort factor of being twice as costly in materials and three times the labor. But it feels better.