Have done 5 transmission drain & fills during past 16 months.
Keeping a record here, to compare notes with other DIY'ers.
Date Temp Drain Fill
5/07 65C 2600 2250
5/12 40C 1600 2000





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The latest D&F was on 5/7, did it 1 hour after the commute, drained out 2600ml, fluid temperature ~65C.
Filled back 3 quarts of new fluid, start car, shifted between gears for a minute,
and then when draining out the excess trans fluid, I closed the overflow plug before reaching "thin stream" to compensate the higher than required fluid temperature (35~42C). Was able to back fill 2250ml at fluid temp ~ 65C.

Probably the transmission is lacking ~300ml of fluid, which means ~3% error, considering 10.5 quarts of total transmission fluid.

ATF fluids are mostly base oil, assuming a thermal expansion coef. of 0.0007, total volume of 10.5QT (9933ml), temperature increase of 40C, the volume expansion is 0.0007*40*9933=278ml, very close to what was observed.

 

I wish Lexus and other brands kept the damn transmission fluid check dipstick. My 2008 has 95K miles and runs very smooth. The Lexus and Toyota dealers wants over $300 to do a flush and fill. I'll problem let them do it for me since the drain and refill at the same amount might not be the correct amount going back in if I do it. Small price to pay vs damaging your transmission

 

thanks a lot for the advice.
wondering if the transmission level accuracy is really that critical,
considering a total of 10.5 quarts of fluids, a 300ml error means 3% of total fluids.

 

 

 

The Toyota dealership is charging the same as the Lexus dealership? You should not have a issue if you take 2 identical clear containers, drain into one, then fill the other with the same exact amount of new fluid and put it back in, I don't think there is any way they are so sensitive that a little more or less fluid is going to harm it especially when they hold so much fluid.

 

 

Well he's wrong about the filter in a LS460 not being replaceable. I bought a paper filter and I changed a paper filter and it was not a dream.

 

 

LS460 transmission fill temperature range is

35-42C

If you are filling at 65C, you have undefiled.
It doesn't really matter at what temperature you are draining. Filling needs to be in the range.

(LS430 transmission fill range is 45-55C)

 

 

Just be aware that this only applies in the US of A. Here in Canada and everywhere else in the world, the manual states regular fluid changes "every 72 months/96,000 kms", (55,000 miles). I have my Maintenance Schedule right on front of me. The fact that the US is different is only because of marketing. Lexus wants to be competitive with other manufacturers - especially in the US where the market is huge.

I remember when BMW and many others claimed "no maintenance required" on their transmissions (such as my 7 series and X5), until companies like ZF said, "uhhhhh no, you can't do that. Even our transmissions need servicing".

 

 

I have no problem with the BG trans flush cleaning agent or whatever they are using. This doesn't scare me at all. It seems Lexus is calling the paper filter a strainer I get that. I don't even feel its a big deal that nobody is changing the paper filter. In my car I want the paper filter changed though. By the way, the mesh strainer that is in some cars does deteriate and tear. I have seen this happen many times. Nobody ever pulls a pan and even sees the mesh is torn. Not the case in a LS460 because its paper.