I understand the concept of an overflow tube, but given that I have no reason to think that my current fluid level is wrong, why couldn't I replace new fluid by volume of old fluid removed, with both being the same garage temperature? I will be using OEM fluid.
I ask because I plan on doing multiple drain and refills about a week or so apart. I've owned my LX for the past 50K miles, and not one drop of any fluid of any sort is leaking (thank you Toyota/Lexus). The procedure for using the overflow tube seems much more onerous than necessary, again given my fluid levels are undoubtably correct.

Can the overflow tube approach be done on the final drain and refill without much risk? Seems to me the answer is yes. Am I missing something?

 

Replacing fluid by volume is an acceptable technique if you are sure that the fluid level is correct to begin with. I chose to do the drain and fill using the temp check overflow method because I already had an OBD reader for the trans temp. If you plan to do multiple drain and fill, you might as well do it all at once. Drain and fill, then start the car and run through the gears a few times and then drain and fill again until you are satisfied. The reason is, the most amount of work for this job is taking apart all the covers and particularly the cover over the fill port. In this way, you can just put in the same amount of fluid until the final check and just use the overflow tube once. If using the temp check method you dont even have to measure the fluid for a drain and fill. Just drain the fluid, resinert the overflow tube, fill until fluid comes out, insert plug and run through the gears, then drain and fill again. Temp check after the last drain and fill.

 

I am unclear how you know your fluid level is correct, if you have not checked it? It is not uncommon to find the factory fill off, or prior service get it off. I opened an a760H recently that had been shop serviced 25k miles prior, and it was a quart low. Others have reported the same on the initial service post-factory. Your LX from the Tahara plant would hopefully have had better quality control and had a 2nd quality check.

It is not unreasonable to assume it’s close, though, and do as your suggested - replace the volume, then do a final check after the 2nd one. Or your could verify the fill level on the 1st, then do the volumetric swap the 2nd time. The temperature does not have to be a tremendous hassle. Five minutes of slow driving on a typical transmission will raise it to 100 to 110F, starting from 60 to 70F (I’ve tested this on my own SUV). It cools VERY slowly once heated, so you could do just do it that way. The thermal expansion rate of ATF is quite small in fact; shifting through the gears to get the valve body filled before the check is in fact more important. IME that can account for a 1/2 quart error (underfill) right there.

 

I wonder if anyone has replaced the transmission oil at the dealership?
What is your model year? and what was the cost?

 

I have seen people go to dealer for it, but really I think it’s really not the best option. There is of course a drain and fill procedure in the Toyota manual but the first thing I hear is that the dealership will say it’s lifetime fill and not needed to be done. Then you argue and request the price and it will be outrageous for sure, 500 dollars? Something like that. You are really best to find another shop that works on Toyotas and have them do it, at least they will probably want to do it because most mechanics actually recommend some kind of transmission service as maintenance. I did it at home with jack stands and drowned and filled twice probably took 2 hours. A shop could be done in a hour really. That’s just my thought

 

I did it this way on my 2007 SC430, do you think i could do it the same way on the LX570?
https://www.clublexus.com/forums/sc4...l#post11607286

 

yes you can do the complete drain that way, many people have done it. I guess maybe the location of the lines to use might be slightly different but there are write ups. There is some thought that swapping all the fluid out is not recommended, but it’s not universal consensus.